QiLing Tools🧰All Tools
787 tools, grouped by category. Everything runs inside your browser; files are never uploaded to a server.
📄PDF Tools76 tools
View all →🧩Merge PDFFree online PDF merger: combine several PDF files into one in the order you choose, with reordering. Processed locally in your browser, no upload, no sign-up.✂️Split / Extract PDFFree online PDF splitter: extract a page range into a new PDF, or split every page into its own file and download them as a ZIP. Processed locally.🔄Rotate PDFFree online PDF rotator: rotate all or selected pages by 90°, 180° or 270° to fix scanned documents. Processed locally, no upload.🖼️PDF to ImageFree online PDF to image converter: render every page as a high-resolution JPG or PNG at 72/150/300 DPI, download all as a ZIP. Processed locally, no upload.📑Image to PDFFree online image to PDF converter: combine JPG, PNG and WebP images into one PDF in order, with A4 or image-sized pages. Processed locally, no upload.🗜️Compress PDFFree online PDF compressor: re-render pages with compressed images to shrink scanned and image-heavy PDFs, with adjustable quality. Processed locally.💧Watermark PDFFree online PDF watermark tool: add text watermarks to every page, tiled or centred, with opacity and angle controls. Any language, processed locally.🗑️Delete PDF PagesFree online tool to delete PDF pages: remove pages by number or range and keep the rest, then download. Processed locally, no upload.📃Extract PDF TextFree online PDF text extractor: pull all text from a text-based PDF page by page, copy it or download as TXT. Parsed locally, never uploaded.🗂️Organize PDF PagesFree online PDF page organizer: every page as a thumbnail — drag to reorder, rotate or delete single pages, then export a new PDF. Runs locally.🔢Add Page Numbers to PDFFree online PDF page numbering tool: add page numbers choosing the position, style, font size, starting number, page range and custom template. Runs locally.✍️Sign & Stamp PDFFree online PDF signing tool: drop in a handwritten signature or company stamp, drag it into place on a page preview, adjust size and opacity, then export.🧧PDF Cross-Page SealStamp a cross-page seal on a PDF for free: the seal is sliced by page count, one slice per page edge, so fanned pages rebuild it and no page can be swapped.📝PDF EditorFree online PDF editor: click text on the page to change or delete it, with the old text truly removed and the rest of the page untouched. Add text, images and cover boxes too.🔳Multiple Pages per SheetFree online PDF N-up tool: lay 2, 4, 6 or 9 pages onto one sheet with a choice of A4 orientation, margins and gaps to save paper. Runs locally, never uploaded.🔲Crop PDFFree online PDF cropper: detect each page's content area and trim the white space, or set margins by hand with a live preview. Stays vector, text selectable.🔒Encrypt PDFFree online PDF encryption: set an open password and restrict printing, copying, editing and annotating with AES-256. Everything runs on your device.🔓Unlock PDFFree online PDF unlocker: enter the password you already know and export a PDF without it, or lift owner-only limits on printing and copying. Runs locally.🏞️Extract PDF ImagesFree online PDF image extractor: pull embedded pictures out at their original resolution as PNG or JPG, with fragment filtering and duplicate removal.📐Resize PDF PagesFree online PDF page resizer: put mixed-size pages onto one paper size — A4, A3, Letter or custom — scaled proportionally and centred, with optional margins.🏷️Edit PDF PropertiesFree online PDF metadata editor: view and change the title, author, subject and keywords, or wipe every property and timestamp for privacy. Runs locally.🌓PDF to Black & WhiteFree online PDF grayscale converter: turn a colour PDF into grayscale or pure black and white, with adjustable threshold, brightness and live preview.🔤Add Text to PDFFree online tool to add text to a PDF: click the page to type, then drag, resize, recolour or bold it. Chinese supported and the pages stay vector.🧱Flatten PDFFree online PDF flattener: lists every form field so you can fill it in first, then turns the form into plain page content, optionally rasterizing each page.📰PDF Header & FooterFree online tool to add headers and footers to a PDF: text left, centre or right with {page}, {total}, {date} and {filename} variables, plus a separator line.➕Insert Pages into PDFFree online tool to insert pages into a PDF: add blank pages, images or pages from another PDF at the start, the end or around page N, or interleave two scans.⬛Redact PDFFree online PDF redaction: draw boxes over names, ID numbers or amounts and black them out for good — those pages are re-rendered so the text is gone.📜PDF to Long ImageFree online PDF to long image converter: stack the pages you pick into one tall JPG or PNG, with adjustable width, gap and background. Huge results auto-split.🖨️Photo Print LayoutFree online photo print layout: tile ID photos at 300 DPI onto 4×6, 5×7, A4 or Letter paper with gaps, cut lines and copies, then export JPG or PDF.📖PDF Booklet MakerFree online PDF booklet maker: reorder pages for saddle-stitch printing, two up on landscape sheets padded to a multiple of four, duplex or separate sides.🔖PDF Bookmarks EditorFree online PDF bookmark editor: read the outline, then add, rename, nest and reorder bookmarks, set pages by clicking thumbnails, or paste a table of contents.🔬Compare PDFFree online PDF compare: see every added and removed word highlighted page by page, plus a pixel diff that boxes changed images and layout in red.👁️PDF OCRFree online PDF OCR: recognise English, Chinese and digits in scanned PDFs in your browser and add an invisible text layer, so pages become searchable. Local.📨PDF Overlay & LetterheadFree online PDF overlay tool: put a letterhead, background, watermark or stamp behind or in front of every page, with page range, scaling and opacity.🌙PDF Dark ModeFree online PDF dark mode converter: turn black-on-white PDFs into light-on-dark pages, with hue-preserving, sepia or custom colours. Text stays selectable.🔎PDF Info & InspectorFree online PDF inspector: version, page count and sizes, metadata, encryption, permissions, fonts, images, form fields and attachments, as a JSON report.🧹Remove Blank Pages from PDFFree online tool to remove blank pages from a PDF: it finds empty and near-blank scans, marks them on thumbnails you can toggle, sensitivity adjustable.📽️PDF to PowerPointFree online PDF to PowerPoint converter: every page becomes a high-resolution slide in a real .pptx, sized to the page or 16:9, with the text as speaker notes.📝PDF to WordFree online PDF to Word converter: turn a PDF into an editable .docx keeping paragraphs, headings, bold and italic, lists, images and page breaks. Runs locally.🖊️Annotate PDFFree online PDF annotator: highlight, draw, add shapes, arrows, sticky notes and text boxes, then save as editable annotations or flatten them. Runs locally.📎PDF AttachmentsFree PDF attachment manager: list embedded files with size and description, download one or all as ZIP, attach new files or remove old ones. Runs locally.🧼Sanitize PDFFree PDF sanitizer: find and remove JavaScript, auto-run and launch actions, links, attachments, comments, forms and metadata, with a before/after report.📗PDF to ExcelFree PDF to Excel converter: detects ruled and borderless tables, lets you adjust columns, turns numbers into real values and exports XLSX or CSV. Runs locally.☑️Create PDF FormMake any PDF fillable: draw text fields, checkboxes, radio buttons, dropdowns, date and signature fields; set names, required flags and tab order. Free, local.🧷PDF Poster PrintingEnlarge a PDF page and tile it across A4, A3 or Letter sheets with overlap, crop marks, A1/A2 labels and an assembly guide. Vector output, free and local.🪓Advanced PDF SplitterSplit a PDF by bookmarks, maximum file size, every N pages, odd/even pages, blank separator pages or a keyword/regex. Preview the parts, download a ZIP.Ⓜ️PDF to MarkdownConvert PDF to clean Markdown for ChatGPT, Claude and other LLMs: headings, lists, bold/italic, GFM tables and links, minus headers and footers.📘Markdown to PDFConvert Markdown or plain text to PDF online with a live paginated preview, three themes, paper and margin options, headers, page numbers and a TOC.🔃Merge Scanned Fronts & BacksCombine a fronts PDF and a backs PDF from a single-sided scanner into correct duplex order, with reversed backs, 180° rotation, blank padding and preview.📚PDF to EPUBConvert PDF to a reflowable EPUB 3 e-book online: rebuilt paragraphs and headings, chapters from bookmarks, no headers or footers, images, cover and metadata.📇Bates NumberingAdd Bates numbers to PDFs: prefix, suffix, zero padding, numbering continued across files, 6 positions, white box, files renamed by range plus a CSV index.💥PDF ⇄ CBZ ComicsConvert comics both ways: PDF to CBZ with lossless page extraction, CBZ/ZIP to PDF with natural sort, A4/B5 fit and manga order, images to CBZ + ComicInfo.xml.📠Deskew PDFStraighten skewed scanned PDFs and images: per-page skew detection (±15°, 0.1° steps), before/after preview, manual override, border removal, original sizes.🔟PDF Page LabelsEdit PDF page labels: decimal, Roman, letter or prefix-only ranges with custom start numbers. Reads existing labels and previews every page’s label.📻PDF Read AloudListen to a PDF read aloud sentence by sentence, highlighted in the text and on the page. Choose voices and speed, click to jump, and resume later.🕸️PDF to HTMLConvert PDF to HTML: semantic reflowable pages with headings, lists, tables and images, or a fixed layout with selectable text. Single file or ZIP.⛶Add PDF MarginsAdd margins and a binding gutter to PDF pages: per side in mm, in or pt, mirrored for duplex, enlarge page or shrink content, background color, cut lines.🩻Scanned Look PDFGive a digital PDF a scanned or photocopied look: seeded random tilt, grayscale or color, paper tint, grain, blur, toner specks, edge shadow and live preview.📔Split PDF SpreadsSplit book-spread scans into single pages: left/right or top/bottom, auto gutter detection with per-page tweaks, right-to-left order, no recompression.✳️PDF to SVGConvert PDF pages to SVG: paths, colors, gradients and patterns stay vector, text stays editable, images embedded. Image + text-layer mode, SVG or ZIP.🆎PDF FontsSee which fonts a PDF uses: type, embedding, subset, encoding and ToUnicode per page, with copy/search warnings. Extract embedded fonts as TTF, OTF, CFF or PFB.🏎️Optimize PDFLosslessly shrink PDFs: merge duplicate fonts and images, Flate-compress streams, pack object streams, drop unused data, optionally downsample big images.🫧Remove PDF WatermarkRemove watermarks from your own PDFs: detects watermark annotations, layers, artifacts and text or images repeated on each page, then deletes them cleanly.🔎PDF Find and ReplaceFind and replace text in a PDF for free: fix dates, names, prices or typos, or delete text. Old text is truly removed and the rest stays put. Runs locally.🩹Repair PDFFix corrupt PDFs that won’t open: diagnoses header, xref, trailer and truncation problems, rebuilds the xref and page tree, re-renders as a last resort. Free.📕PDF Table of ContentsCreate a clickable table of contents page for a PDF from bookmarks or detected headings: editable levels and pages, dotted leaders, links that stay correct.♿PDF Accessibility CheckerCheck PDF accessibility: tags, language, title, fonts, alt text, headings, form tooltips, links and scanned pages. Apply safe fixes and export a report.📬PDF Form Mail MergeFill a PDF form from CSV rows: auto-matched fields, checkboxes, radios, dropdowns, CJK text, optional flattening, one PDF per row or combined; export form data.🪝PDF Link ManagerList every link in a PDF with its anchor text, export CSV, check URL format, edit or delete links, draw new links and auto-link plain-text URLs and emails.ΣPDF Word CountCount PDF words Word-style for English and CJK: characters, sentences, paragraphs, per-page chart, reading time, keywords and Flesch readability score.🛫PDF Preflight CheckFree online PDF preflight: bleed and TrimBox, effective image DPI, RGB/CMYK/spot colors, fonts, transparency, overprint, hairlines and print permission.🎟️Add QR Codes to PDFStamp a QR code on every PDF page: content from page number, file name, date or your own ID, drawn as crisp vectors, upright on rotated pages, batch files.🎖️PDF Signature VerifierVerify PDF digital signatures: recompute digests, check RSA/ECDSA signatures, view the certificate chain, timestamps and LTV data, and spot edits after signing.🧧Chinese E-Invoice ExtractorBatch-extract Chinese VAT and digital e-invoice PDFs: number, date, buyer, seller, tax IDs, amounts, line items; QR cross-check, duplicates, CSV.📤Rename PDFs by ContentBatch rename PDFs by content: put dates, invoice or order numbers, emails, totals, titles or labelled text into a name pattern; preview clashes.🚩Split PDF by Separator SheetsSplit a batch-scanned PDF at QR or barcode separator sheets, blank pages or marker text; keep or drop separators, name files from QR, print sheets.
🖼️Image Tools116 tools
View all →🖼️PDF to ImageFree online PDF to image converter: render every page as a high-resolution JPG or PNG at 72/150/300 DPI, download all as a ZIP. Processed locally, no upload.📑Image to PDFFree online image to PDF converter: combine JPG, PNG and WebP images into one PDF in order, with A4 or image-sized pages. Processed locally, no upload.🗜️Compress ImageFree online image compressor: batch compress JPG, PNG and WebP with adjustable quality and a max size, showing the before and after sizes. Runs locally.📐Resize ImageFree online image resizer: batch resize by pixel width and height or by percentage with the aspect ratio locked. JPG, PNG and WebP, processed locally.🔁Convert ImageFree online image converter: batch convert JPG, PNG, WebP, GIF and BMP images to JPG, PNG or WebP. Processed locally, no upload.💧Watermark ImageFree online image watermark tool: batch add text watermarks with position, tiling, opacity, size and color settings. Processed locally, no upload.🧱Stitch ImagesFree online image stitcher: join screenshots or photos vertically or horizontally into one long image, with gap and background options. Processed locally.✂️Remove BackgroundFree online background remover: AI finds people, products and animals and cuts the background to a transparent PNG, or swaps in a white, red or blue backdrop.📸Video ScreenshotFree online video frame grabber: enter a timestamp and save that frame as a full-resolution PNG or JPG. Processed locally, no upload.📱QR Code GeneratorFree online QR code generator: turn URLs, text, Wi-Fi or contact cards into QR codes with custom size, colour and error correction. Crisp PNG or vector SVG.🔄Rotate / Flip ImageFree online image rotate and flip tool: rotate JPG, PNG and WebP by 90, 180 or 270 degrees either way, flip horizontally or vertically, batch supported.🔲Crop ImageFree online image cropper: drag on the image to select any area and download the crop. Supports JPG/PNG/WebP, keeps the original format, processed locally.🎨Adjust Image ColoursFree online image colour adjuster: tune brightness, contrast and saturation, or apply black & white, sepia, invert, warm and cool filters with a live preview.🟫Blur / Pixelate ImageFree online image redaction tool: drag to mark any area and hide it with pixelation, blur or a black box — several areas at once, for faces and plates.⭕Round Image CornersFree online tool to round an image's corners or crop it into a circle avatar. Adjustable radius, transparent PNG output, batch supported. Runs locally.🖼️Add Border to ImageFree online tool to add a white or coloured border to photos, pad an image to a square for Instagram, or make a Polaroid-style frame. Batch supported.#️⃣Split Image into GridFree online image grid splitter: cut a picture into a 3×3 grid for Instagram, or 2×2, 1×3, 2×3 and more. Tiles are numbered in order and zipped. Runs locally.🕵️Remove EXIF DataFree online EXIF viewer and remover: see the camera, capture time and GPS location hidden in a photo, then strip the metadata losslessly before sharing.🎯Image Color PickerFree online image colour picker: click anywhere on an image to get its HEX, RGB and HSL values, and extract the dominant colour palette automatically.🧬Image to Base64Free online image Base64 converter: turn an image into a Base64 string or Data URI with ready CSS and HTML snippets, or decode Base64 back to a file.⭐Favicon GeneratorFree online favicon generator: turn a PNG, JPG or SVG into a multi-size favicon.ico plus Apple Touch, Android and PWA icons, a webmanifest and the HTML tags.🪪ID Photo MakerFree online ID and passport photo maker: AI replaces the background with white, blue or red, crops to passport, visa and 1-inch sizes at 300dpi, prints a sheet.🎚️Compress to SizeFree online tool to compress an image to an exact file size: enter a target in KB and the photo is squeezed under it, keeping as much detail as it can.🪄Remove White BackgroundFree online tool to make a white or solid-colour background transparent with smooth, halo-free edges — ideal for signatures, stamps, logos and product shots.🧩Photo CollageFree online collage maker: arrange several photos into one grid image with adjustable columns, cell shape, spacing and background. Drag to reorder.🎞️GIF MakerFree online GIF maker: turn a series of images into an animated GIF with adjustable frame time, size, looping and bounce playback. Drag to reorder.📏Split Long ImageFree online long image splitter: cut long screenshots and posters by piece count, fixed height or phone screen ratio, numbered in order and zipped.🍏HEIC to JPGFree online HEIC to JPG converter: batch-convert iPhone HEIC / HEIF photos to JPG, PNG or WebP with correct orientation, so they open anywhere. Runs locally.🔷SVG to PNGFree online SVG to PNG converter: export SVG vectors to crisp PNG, JPG or WebP at 1x–8x scale or any width, with a transparent or white background. Batch ready.✨Screenshot BeautifierFree online screenshot beautifier: add gradient backgrounds, padding, rounded corners, shadows and macOS or browser window frames. Runs locally, no upload.✏️Photo to SketchFree online photo to sketch converter: turn photos into pencil sketches, clean line art or coloured-pencil drawings, with adjustable stroke width and depth.🔍Sharpen ImageFree online image sharpener: an unsharp mask brings back detail and edges in slightly blurry photos, with amount, radius and threshold and a 1:1 preview.👾Pixel Art MakerFree online pixel art generator: turn photos into retro pixel art with adjustable pixel size and palettes, plus an optional grid for bead or cross-stitch.🔠ASCII Art GeneratorFree online ASCII art generator: convert images into text art with adjustable width and character sets, optional inversion, and copy or download as TXT or PNG.💬Add Text to ImageFree online tool to add text to images: drag text boxes anywhere, with size, colour, outline, shadow and several fonts, plus a classic top/bottom meme template.🌫️Blur BackgroundFree online background blur: AI finds the person, pet or product and blurs only the background for a DSLR look, or leaves the subject alone in colour.↔️Compare ImagesFree online image comparison tool: drag a divider between two images to check edits, compression or grading, and export side-by-side or split before/after.📷QR Code ScannerFree online QR code scanner: upload or paste a screenshot to decode the QR codes inside, read the link or text and copy it. Batch supported, decoded locally.🖨️Change Image DPIFree online DPI changer: set the resolution tag of a JPG or PNG to 300, 350, 72 or any value without touching the pixels, with the print size in millimetres.🔤Image to Text (OCR)Free online OCR: pull Chinese, English and numbers out of screenshots, photos and scans, then copy or download as TXT. The model runs in your browser.💳ID Card CopyFree online ID card copy maker: front and back laid out at the real 85.6×54mm on one A4 page, with an optional anti-misuse watermark. Export JPG or PDF.🔎AI Image UpscalerFree online AI image upscaler: enlarge photos and screenshots 2x or 4x with Real-ESRGAN, clearing blur and compression noise. The model runs in your browser.📄Document ScannerFree online document scanner: detect the page in a phone photo, straighten it with perspective correction, remove shadows, and export a scan, JPG or PDF.🧽Remove Watermark / ObjectFree online watermark and object remover: paint over watermarks, date stamps or small objects and the area is filled in from the surrounding background.🖌️Replace ColourFree online colour replacer: click a colour in your image and swap it for another while keeping the shading and texture — for clothes, logos and products.🏞️Extract PDF ImagesFree online PDF image extractor: pull embedded pictures out at their original resolution as PNG or JPG, with fragment filtering and duplicate removal.📊Barcode GeneratorFree online barcode generator: Code 128 with automatic code sets, EAN-13 with its check digit and Code 39. Adjust size, quiet zone and colours; SVG or PNG.📜PDF to Long ImageFree online PDF to long image converter: stack the pages you pick into one tall JPG or PNG, with adjustable width, gap and background. Huge results auto-split.ℹ️Image Info ViewerFree online image info and EXIF viewer: dimensions, file size, format, bit depth, DPI and ICC profile, plus camera, lens, exposure, date, GPS and a histogram.🎨Image Color PaletteFree online colour palette extractor: find the 3–16 dominant colours with percentages, copy HEX / RGB / HSL and export CSS variables, JSON or a PNG strip.🖨️Photo Print LayoutFree online photo print layout: tile ID photos at 300 DPI onto 4×6, 5×7, A4 or Letter paper with gaps, cut lines and copies, then export JPG or PDF.📱Social Media Image ResizerFree online social media image resizer: crop one image to 20 platform sizes — YouTube thumbnail, Instagram, X, Facebook, LinkedIn, TikTok — exported as a zip.📝Text to ImageFree online text to image tool: turn a quote or long post into a clean image with paper, dark, gradient, notebook and mint themes and smart line wrapping.📊Chart MakerFree online chart maker: paste data from Excel or CSV to build bar, line, area, pie, donut and scatter charts, then download a 2× PNG or an editable SVG.🎞️Video to FramesFree online video frame extractor: export every frame, every Nth frame or N frames per second as PNG or JPG, within a time range, all zipped up.📲App Icon GeneratorFree online app icon generator: turn one 1024px image into an iOS appiconset, Android mipmaps and adaptive icons, PWA icons, a Windows ICO and a macOS ICNS.🎬GIF EditorFree online GIF editor: delete, duplicate and reorder frames, change delays, reverse, boomerang, crop, resize and set the loop count, then re-export the GIF.🖋️Signature MakerFree online e-signature tool: photograph a handwritten signature for a clean transparent PNG with paper and shadows removed, or draw one and export PNG or SVG.🧱CSS Sprite GeneratorFree online CSS sprite generator: pack icons into one sheet with bin packing, grid or row layouts and @2x support, and get the CSS positions, or slice one.🎞️Photo FiltersFree online photo filters: 13 looks — vintage film, black & white, noir, sepia, warm, cool, teal & orange, Lomo, faded — previewed on your photo, batch ready.📷Camera Info FrameFree online camera watermark maker: reads brand, model, focal length, aperture, shutter, ISO and date from EXIF and adds an info bar or clean border.✒️Image to SVGFree online image to SVG converter: trace PNG and JPG bitmaps into scalable vectors, with presets for line art, logos and photos and adjustable smoothing.✨Image DenoiserFree online photo noise reduction: clear luminance grain and colour blotches from low-light shots with edge-preserving filtering, compare at 1:1, batch ready.🏁Image DitheringFree online image dithering: turn photos into 1-bit black & white, 4-level grey, e-ink or Game Boy palettes with Floyd–Steinberg, Atkinson or Bayer ordering.🙈Blur FacesFree online face blurring: AI finds every face in a photo, including small ones in group shots, and pixelates, blurs, blacks out or covers them with an emoji.🪄Auto Enhance PhotoFree online one-click photo enhancer: auto white balance, auto levels, auto exposure and smart vibrance, each photo analysed on its own. Batch ready.🖼️Photo to Oil PaintingFree online photo to oil painting converter: a Kuwahara filter adds brush strokes, with adjustable brush size, colour richness and optional canvas texture.🏙️Tilt-Shift EffectFree online tilt-shift effect: blur the top and bottom while one band stays sharp, then boost colours, turning streets and crowds into toy-like miniatures.🕵️Image SteganographyFree online image steganography: hide a message in the least significant bits of a PNG, optionally AES-256 encrypted, and reveal hidden text again.🎯Smart CropFree online smart crop: finds the subject and keeps faces in frame while batch-cropping to 1:1, 4:5, 3:4, 9:16, 16:9 or a custom ratio, with fixed output width.🌗Duotone / Gradient MapFree online duotone tool: map brightness to a gradient between two or three colours, with 10 ready-made schemes or your own shadow and highlight colours.🔴Halftone EffectFree online halftone generator: turn photos into dot patterns — one-colour dots, four-colour CMYK screens or a line screen — for comic and vintage print looks.📺Glitch EffectFree online glitch art generator: add RGB split, tearing, corrupted blocks, noise and scanlines, each with its own strength, or randomise it in one click.🌲Double ExposureFree online double exposure maker: blend a portrait with a landscape or texture using screen, multiply, overlay or soft-light, with opacity, zoom and position.🏷️Sticker OutlineFree online sticker maker: add an even white outline and a soft drop shadow around a transparent PNG; photos get their background removed by AI first.📐Straighten ImageFree online image straightener: rotate by any angle to 0.1°, auto-detect tilted horizons, then crop the empty corners or fill them, with a guide grid.🪞Mirror & KaleidoscopeFree online mirror effect tool: flip and copy an image's left, right, top or bottom half for symmetry, go four-way, or make 4–24 segment kaleidoscope patterns.🧩Photo MosaicFree online photo mosaic maker: rebuild a picture out of hundreds of small photos, matched by colour and spaced to avoid repeats, with adjustable grid size.🧵Cross-Stitch Pattern MakerFree online cross-stitch pattern generator: turn photos into charts with coloured cells, symbols and numbering, a colour key with stitch counts and a preview.📈Curves AdjustmentFree online curves tool: drag points on the RGB master curve and each channel over a live histogram, with presets for S-curve contrast, faded film and invert.🎚️Apply LUT (.cube)Free online LUT tool: load a .cube or Hald CLUT PNG and apply it to photos with trilinear interpolation, adjustable strength, live preview and batch processing.👁️Color Blindness SimulatorFree online colour blindness simulator: view images as protanopia, deuteranopia, tritanopia or achromatopsia, adjust severity and compare every type.🖍️Line Art ExtractorFree online line art extractor: turn photos and illustrations into clean black-and-white line drawings, with adjustable thickness, detail and speck cleanup.🧩Jigsaw Puzzle MakerFree online jigsaw puzzle maker: cut a photo into 12–1000 tabbed pieces and export a printable sheet with cut lines, an SVG cutting template or loose PNGs.🗂️Video Contact SheetFree online video contact sheet maker: tile N×M evenly spaced frames into one image, each with a timestamp, under a header of file and stream details.☁️Word Cloud GeneratorFree word cloud maker: paste text or open a file, word counts with stopword removal, editable frequency table, heart, star or image shapes, PNG and SVG.👤Avatar GeneratorFree avatar generator: initials colored by name (CJK aware), GitHub-style identicons and geometric avatars. Circle or square, batch ZIP, PNG/SVG.🌄Wallpaper & Background GeneratorFree wallpaper generator: mesh and linear gradients, blobs, waves, low poly, hexagons, dots, stripes and grain. Palettes, 4K sizes, PNG/JPG/SVG.🦸Photo to CartoonFree photo to cartoon converter: smooth flat colors and bold outlines, with comic, anime and watercolor presets, live preview and batch export.😂Meme GeneratorFree meme maker for your own images: classic Impact top and bottom text, a modern caption bar, and draggable, rotatable text and emoji stickers. PNG/JPG.🏹Screenshot AnnotatorFree screenshot annotator: paste with Ctrl+V, add arrows, boxes, numbered steps, highlighter and text, pixelate or blur secrets, crop, copy or save PNG/JPG.🕰️EXIF EditorFree EXIF editor: view all JPEG tags, change or bulk-shift the date taken, set or remove GPS, edit camera, artist and copyright, with no recompression.⬜Placeholder Image GeneratorFree placeholder image generator: custom size, colors and text with auto-fit font, PNG, JPG, WebP or SVG, batch sizes to ZIP, or copy a data URI or SVG.🧑💻Code ScreenshotTurn code into beautiful images: auto-detected syntax highlighting, 10 themes, macOS window, line numbers, gradient backgrounds, PNG up to 4x or SVG.🎴Video Thumbnail MakerFree video thumbnail maker: pick any frame or upload an image, add bold titles with outline, bars, emoji and gradients, sized for YouTube, TikTok and more.🦚Color TransferCopy a reference photo’s color grade onto your images with Reinhard, histogram matching or MKL. Adjustable strength, batch mode and .cube LUT export.🌆Panorama StitcherStitch 2–10 overlapping photos into a panorama: automatic order and alignment, cylindrical projection, exposure compensation, seamless blending, auto-crop.🔮QR Code Art GeneratorFree styled QR code maker for URLs, Wi-Fi, vCards, email, SMS and maps: dot or diamond modules, custom eyes, gradients, logo, PNG/SVG/JPG and a scan check.💌Text to HandwritingFree text to handwriting converter: natural size, tilt and ink variation on lined, grid, kraft or letter paper, auto pages, scan/photo look. PNG, ZIP, PDF.💄Portrait RetouchFree portrait retouching: AI face detection, edge-preserving skin smoothing, brighten and even tone, teeth and eyes, click-to-heal blemishes, slim face.🧍Text Behind ImageFree text behind image maker: AI cuts out the subject so big text sits between background and person. Multiple layers, stroke, shadow, glow; full-res PNG/JPG.👯Duplicate Photo FinderFind duplicate and similar photos in your browser: SHA-256 for identical files, perceptual hashes for resized or recompressed copies; keep the best, export CSV.🌃HDR MergeMerge 2–7 bracketed exposures with MTB alignment, Mertens exposure fusion and ghost reduction — no camera response needed — or give one photo an HDR look.🎦Film Negative ConverterConvert scanned film negatives to positives online: orange mask removal, per-channel auto balance, white balance, tone curves, dust removal and batch export.🌁Pixel SortingPixel sort images online: sort by brightness, hue or RGB within threshold, edge, random or brush-mask intervals at any angle, seeded, with full-res PNG export.🧑🎨Drawing Grid MakerAdd an artist’s drawing grid to a photo: count or cm/in cells, diagonals, thirds, golden ratio, labels, value study, and print to scale across pages.♾️Seamless Texture MakerMake photos and textures tile seamlessly: mirror tiling, cross-fade edges or patch-based seam healing, offset and tiled previews, plus a repeat-pattern maker.🪵Procedural Texture GeneratorProcedural textures online: Perlin/Simplex fBm, ridged, turbulence, Worley, domain warp, 10 presets, colour ramps, seamless tiling, 4096 PNG and normal maps.🧇Social Feed Grid PlannerPlan your profile grid: reorder a 3-column feed, waterfall or 9-photo post, schedule dates and captions, check colour harmony, split puzzle grids and carousels.📴Device Mockup GeneratorPut screenshots into phone, tablet, laptop, monitor, browser and watch frames online, with 3D perspective tilt, multi-device scenes and 4K PNG export.🏃Sprite Sheet AnimatorAnimate sprite sheets online: auto-detect the grid, set frame order, fps and onion skin, export GIF, APNG, WebP or frames — or pack frames into a sheet + JSON.⚜️Logo MakerFree logo maker: round badges with curved text, shield, hexagon and ribbon shapes, 68 line icons or emoji, monograms, palettes, SVG and transparent PNG.⚫Poster Print (Rasterbator)Print one image across many A4 or Letter pages: page grid or width, overlaps, cut marks, A1/B2 labels, rasterbator-style halftone dots, PDF or print.💞Shape Photo CollageTurn photos into a heart, star, letters, numbers or any silhouette: grid or packed circles, spacing, rotation, borders, seeded shuffle, PNG up to 4000 px.⚡Batch Image ProcessingFree online batch image tool: run a whole folder of photos through resizing, a text watermark, JPG/PNG/WebP conversion and numbered renaming, download as ZIP.🔴Seal ExtractorFree online seal extractor: lift a red or blue stamp off a scan into a transparent PNG, dropping paper, tint and specks. Solid colour, auto-trim, runs locally.
🎵Audio Tools50 tools
View all →🔁Convert AudioFree online audio converter: convert between MP3, WAV, M4A, AAC, FLAC, OGG and OPUS with selectable bitrate. Powered by FFmpeg, processed locally, no upload.✂️Trim AudioFree online audio trimmer: set start and end times to cut a clip from MP3, WAV, M4A and more. Make ringtones. Processed locally, no upload.🧩Merge AudioFree online audio merger: join MP3, WAV and other audio files in order into one file, mixed formats supported. Processed locally, no upload.🔊Volume / SpeedFree online audio volume booster: amplify or reduce volume and change playback speed (0.5x to 3x without pitch change). Processed locally, no upload.🌗Audio Fade In/OutFree online audio fade tool: add a fade-in at the start and a fade-out at the end of MP3, WAV and more, with any length. Batch supported, runs locally.📊Normalize AudioFree online loudness normalizer: bring a batch of files to the same perceived loudness with EBU R128 / LUFS, or even out uneven speech with compression.🔪Split AudioFree online audio splitter: cut long recordings, album rips and audiobooks into parts by count, fixed length or specific time points, downloaded as a zip.🎚️Mix AudioFree online audio mixer: play voice, a backing track and background music together, with adjustable levels and a built-in limiter. Processed locally.🎼Change Audio PitchFree online pitch shifter: move a song or recording up to 12 semitones up or down while keeping the tempo — for transposing backing tracks and voice changing.🧹Reduce Audio NoiseFree online audio denoiser: strip air-conditioning hum, hiss and fan noise from recordings, with adjustable strength and optional speech boost. No upload.🤫Remove SilenceFree online silence remover: cut the dead air at the start and end of a recording and shorten long pauses in the middle, with an adjustable threshold.🎛️Audio EqualizerFree online audio EQ: adjust bass, mid and treble gain separately, with bass boost, vocal, bright, warm and telephone presets and a built-in limiter.🎵Extract AudioFree online tool to extract audio from MP4, MOV and other videos as MP3, M4A or WAV. Processed locally, no upload.🔇Mute VideoFree online video muter: remove the audio track from a video in one click without re-encoding the picture. Finishes in seconds, processed locally, no upload.🎙️Replace Video AudioFree online tool to replace a video soundtrack or layer music over the original audio, with adjustable volume and looping. The picture is not re-encoded.🔊Text to SpeechFree text to speech: near-human AI voices run in your browser, unlimited, downloadable as WAV, in English and Chinese. System voices cover many more languages.⏪Reverse AudioFree online audio reverser: play MP3, WAV, M4A and more backwards from end to start, with your choice of output format and bitrate. Batch supported, no upload.🎬Audio to VideoFree online audio to video converter: pair an MP3 or WAV with a cover image or solid background and a title, and export a 16:9, 1:1 or 9:16 MP4. Runs locally.〰️Audio Waveform GeneratorFree online audio waveform generator: render MP3, WAV and more as bar, mirrored, line or filled sound-wave images with custom colors and sizes. PNG and SVG.🎙️Online Voice RecorderFree online voice recorder: record from your microphone with noise suppression, pause and resume, a live level meter and waveform, then save as MP3 or WAV.🏷️Audio Tag EditorFree online audio tag editor: edit title, artist, album, year, genre and track number in MP3, M4A, FLAC, OGG and WAV, and replace the cover — no re-encoding.💓BPM DetectorFree online BPM detector: find a song's tempo to 0.1 BPM with a confidence score and half/double-time candidates, see every beat on the waveform, or tap along.🥁Online MetronomeFree online metronome: 20–300 BPM with tap tempo, common and custom time signatures, accents, eighth, triplet and sixteenth subdivisions and three sounds.🔉Tone GeneratorFree online tone generator: sine, square, sawtooth and triangle waves from 1 to 20,000 Hz, a note picker, sweeps, white/pink/brown noise and a WAV download.🎤Vocal RemoverFree online vocal remover: center-channel cancellation turns a track into a karaoke instrumental, with a keep-the-bass option and approximate vocal extraction.🔔Ringtone MakerFree online ringtone maker: drag on the waveform to pick a section and export an iPhone .m4r (up to 40 s) or Android MP3 / OGG, with fades and normalization.🌌Audio SpectrogramFree online spectrogram generator: see time, frequency and level from a Hann-windowed STFT, with FFT size, log axis, dB range and colour maps. Exports PNG.🎧8D Audio ConverterFree 8D audio maker: make any song circle your head with adjustable speed, width and reverb. Preview 15 s, export MP3 or WAV. Best on headphones, runs locally.🎭Audio Effects & Voice ChangerFree voice changer and audio effects: reverb, echo, chorus, flanger, robot, telephone, walkie-talkie, chipmunk, 8-bit and more. A/B preview, batch export.🗣️Speech to TextFree online speech to text: talk into your mic for live transcription in 20+ languages with timestamps, auto punctuation, editing and TXT or SRT export.🍃White Noise & Ambient SoundsFree ambient sound mixer: white, pink and brown noise, rain, ocean, wind, fire, stream, birds, café and fan. Presets, sleep timer, saved mixes, MP3/WAV export.🎶Online PianoFree virtual piano: play with mouse, multi-touch or your computer keyboard, 2–4 octaves, piano, e-piano, organ and synth, sustain pedal, WAV/MIDI export, songs.🔈Audio Channel ToolsFree audio channel tools: stereo to mono (mix or L/R), mono to stereo, swap or split channels, mute one side, balance, fix phase, 5.1 to stereo.📶Loudness MeterFree loudness meter: integrated LUFS, short-term/momentary max, LRA, true peak, RMS, DC offset and clipping, checked against Spotify, YouTube and EBU R128.📢Decibel MeterFree online decibel meter: measure noise with your mic in real time, A/C/Z weighting, fast/slow response, min/max/average/Leq, 60-second graph and calibration.🪘Drum MachineFree online drum machine: 10 synthesized drums, 8/12/16/32-step grid, BPM, swing, accents, mute/solo, rock to bossa presets, export WAV and General MIDI.🎸Online TunerFree online tuner using your microphone: note, octave and cents in real time. Guitar standard, Drop D, Open G, DADGAD, bass, ukulele, violin, A4 415–466 Hz.📻PDF Read AloudListen to a PDF read aloud sentence by sentence, highlighted in the text and on the page. Choose voices and speed, click to jump, and resume later.🪗Audio Compressor & LimiterFree online audio compressor: threshold, ratio, knee, attack/release, auto makeup, true-peak limiter, noise gate, de-esser, presets and A/B preview.〽️LRC Lyrics MakerFree online LRC maker: tap Space to timestamp each line as the song plays, word-by-word enhanced LRC, draggable timeline, karaoke preview, LRC/SRT/VTT export.💿MIDI PlayerFree online MIDI player: play .mid files with a live piano roll, mute or solo parts, change tempo, transpose, view track info and export WAV.🕹️Game Sound Effect GeneratorFree sfxr-style 8-bit sound effect generator: one-click coin, laser, explosion and jump sounds, tweak every parameter, export WAV and share by link.⏭️Jump Cut: Remove Video PausesFree automatic jump cut: detect pauses in talking-head or lecture videos, cut or speed them up with per-cut control, export MP4, EDL and CSV.🎷Audio to MIDITurn humming, whistling, singing or a single instrument into MIDI online: pitch and onset detection, key snapping, quantize, editable piano roll, .mid export.🪩Audiogram MakerTurn podcast, interview or music clips into audiogram videos online: spectrum, waveform or circular visualizer, cover art, captions, progress bar, MP4 export.🪕Chord & Scale FinderFree chord library: every chord type in all 12 keys with guitar and ukulele voicings, piano view, a chord finder for inversions, and scale charts.🟣Circle of FifthsInteractive circle of fifths: key signatures, relative minors, diatonic chords with Roman numerals, playable progressions, transposer and capo tips.➰Seamless Loop MakerMake seamless audio loops online: sample-accurate automatic loop points, zero-crossing snap, crossfades, preview, extend music, WAV with loop points or MP3.👂ABX Blind Listening TestFree online ABX listening test: auto loudness matching and time alignment, seamless switching, loop regions, p-value verdict, blind AB preference, MP3 maker.☎️DTMF TonesGenerate and decode phone keypad tones (DTMF, incl. A–D) online: keypad, WAV export, decode recordings or the mic with timestamps, and decode Morse from audio.
🎬Video Tools54 tools
View all →🗜️Compress VideoFree online video compressor: shrink MP4, MOV and other formats with H.264 encoding and resolution scaling, at the strength you pick. Processed locally.🔁Convert VideoFree online video converter: convert MOV, MKV, AVI, FLV, WebM and more to MP4 or WebM. Powered by FFmpeg, processed locally, no upload.✂️Trim VideoFree online video trimmer: set start and end times to cut a clip; fast mode finishes in seconds without re-encoding. Processed locally, no upload.🎞️Video to GIFFree online video to GIF converter: cut a clip and create a high-quality animated GIF with adjustable frame rate and width. Processed locally, no upload.🎵Extract AudioFree online tool to extract audio from MP4, MOV and other videos as MP3, M4A or WAV. Processed locally, no upload.📸Video ScreenshotFree online video frame grabber: enter a timestamp and save that frame as a full-resolution PNG or JPG. Processed locally, no upload.🔇Mute VideoFree online video muter: remove the audio track from a video in one click without re-encoding the picture. Finishes in seconds, processed locally, no upload.🧩Merge VideosFree online video joiner: combine several MP4, MOV or MKV clips into one file, even when their resolution and frame rate differ. Processed locally.⏩Change Video SpeedFree online video speed changer: slow a clip to 0.25x or speed it up to 4x. The audio follows along with its pitch preserved. Processed locally, no upload.💧Watermark VideoFree online video watermarker: add a text watermark or a logo image with adjustable position, size, opacity, angle and full-frame tiling. Processed locally.🔲Crop VideoFree online video cropper: drag on the frame to select the area to keep, with 1:1, 9:16 and 16:9 presets to turn landscape footage into portrait. Runs locally.🔄Rotate VideoFree online video rotator: turn sideways clips 90° or 180°, mirror them horizontally or flip them vertically. Batch supported, processed locally, no upload.🎙️Replace Video AudioFree online tool to replace a video soundtrack or layer music over the original audio, with adjustable volume and looping. The picture is not re-encoded.🔤Burn SubtitlesFree online subtitle burner: load an SRT or VTT file and hardcode the captions into the video, with adjustable size, colour and outline. No missing glyphs.⏪Reverse VideoFree online video reverser: play a clip backwards with the audio reversed too, for rewind effects. Processed locally in your browser, no upload.🎬GIF to VideoFree online GIF to video converter: turn animated GIFs into MP4 or WebM at a fraction of the size, with repeat count and frame rate options. No upload.🎞️GIF MakerFree online GIF maker: turn a series of images into an animated GIF with adjustable frame time, size, looping and bounce playback. Drag to reorder.🎬Audio to VideoFree online audio to video converter: pair an MP3 or WAV with a cover image or solid background and a title, and export a 16:9, 1:1 or 9:16 MP4. Runs locally.🎨Video Color CorrectionFree online video colour tool: adjust brightness, contrast, saturation, gamma and hue, add sharpening or denoising, or apply black & white and sepia looks.🧽Remove Video WatermarkFree online video watermark remover: box the logo or text and erase it with smart fill, blur or pixelation. Several areas at once, audio untouched.🌓Video Fade In/OutFree online video fade tool: fade in at the start and out at the end, from and to black or white, with the audio fading in step. Batch supported.🔂Loop VideoFree online video looper: repeat a clip N times or stretch it to a set length, usually without re-encoding, and make forward-and-back boomerang loops too.🖼️Picture in Picture VideoFree online picture-in-picture maker: place another video or an image as an inset on your main video, with position, size and margin, and pick the audio mix.📐Resize VideoFree online video resizer: change resolution to 1080p, 720p, 480p or a custom size, and convert to 9:16, 1:1 or 16:9 with blurred bars, colour bars or crop.🖥️Online Screen RecorderFree online screen recorder: capture a screen, window or tab with system and microphone audio, add a webcam bubble, then save as WebM or convert to MP4.🪟Split Screen VideoFree online split-screen video maker: place 2–4 videos side by side, stacked or in a 2×2 grid, with size and frame-rate matching, gap and audio mix.🎞️Video to FramesFree online video frame extractor: export every frame, every Nth frame or N frames per second as PNG or JPG, within a time range, all zipped up.🅰️Add Text to VideoFree online tool to add text to a video: several text layers, each with its own start and end time, dragged into place on a live preview, with fades.🎯Compress Video to SizeFree online video compressor with an exact size target: pick 8, 10, 25, 50 or 100 MB, get the bitrate from the duration and encode two-pass x264 to hit it.🗂️Video Contact SheetFree online video contact sheet maker: tile N×M evenly spaced frames into one image, each with a timestamp, under a header of file and stream details.🩺Video Info (MediaInfo Online)Free MediaInfo-style video inspector: container, duration, bitrate, per-stream codec, resolution, frame rate, HDR hints, audio layout, subtitles and chapters.🌅Photo Slideshow MakerFree online slideshow maker using your photos as they are: custom order and durations, 15 transitions, never-crop Ken Burns, music and per-image captions.⚓Video StabilizerFree online video stabilizer: removes hand-held shake and roll with smoothed camera paths, hardware-accelerated in your browser, with zoom-to-crop borders and a preview.🟩Green Screen RemoverFree online chroma key: click to pick the key color, tune it live, then add a color, image or video background or export transparent WebM, ProRes MOV or PNG.🪚Video SplitterFree online video splitter: split into equal parts, every X seconds, by MB per part or at timeline markers. Fast lossless or frame-accurate mode, ZIP download.🐢Video Frame Rate ConverterFree frame rate converter: convert video to 24, 25, 30, 50, 60 fps or any rate by dropping, blending or motion interpolation, plus smooth 2/4/8x slow motion.🌇Apply LUT to VideoFree video LUT tool: load .cube files (1D/3D) or use built-in looks like teal & orange, warm film, bleach bypass and B&W; adjust intensity, compare, export.🗨️Extract Subtitles from VideoFree subtitle extractor: list embedded tracks in MKV or MP4 with language, format and title, export SRT, WebVTT or ASS, batch to ZIP. No upload.🗯️Subtitle EditorFree subtitle editor: open SRT, VTT, ASS, LRC, SBV or TXT, edit text and timing, shift, two-point sync, fix overlaps, find & replace and convert formats.🎴Video Thumbnail MakerFree video thumbnail maker: pick any frame or upload an image, add bold titles with outline, bars, emoji and gradients, sized for YouTube, TikTok and more.🫥Blur Faces in VideoFree online video face blur: AI detects and tracks every face to blur or pixelate it; keep chosen faces, add regions by hand, export MP4 with audio.🌠Timelapse & Stop Motion MakerFree timelapse maker: speed up videos by factor or target length with deflicker and motion blur, or turn photos into stop motion with onion skin. MP4/GIF.📹Webcam RecorderFree online webcam recorder: choose camera and mic, filters and skin smoothing, countdown, pause, snapshots and a teleprompter that isn’t recorded. WebM/MP4.👀Video CompareCompare two videos in sync: side by side, slider wipe, difference or flicker, frame stepping, per-frame PSNR / SSIM graphs and labeled MP4 export.⏭️Jump Cut: Remove Video PausesFree automatic jump cut: detect pauses in talking-head or lecture videos, cut or speed them up with per-cut control, export MP4, EDL and CSV.🎆Video to Animated WebPConvert video to animated WebP or APNG online: trim, set frame rate, width, quality and loops, estimate size, preview and compare with GIF.📼Video Scene DetectionDetect shot and scene changes in a video online: adjustable threshold, scene thumbnails, contact sheet, CSV and EDL cut lists, YouTube chapters, scene clips.💭Text Video MakerMake animated text and quote videos online: 9:16, 1:1, 16:9; typewriter, word pop, slide-up, zoom; gradient, image or video backgrounds; music; MP4 export.🪩Audiogram MakerTurn podcast, interview or music clips into audiogram videos online: spectrum, waveform or circular visualizer, cover art, captions, progress bar, MP4 export.🤳Auto Reframe VideoConvert landscape video to vertical online: face tracking with smooth camera moves, manual keyframes, 9:16, 1:1 or 4:5, blurred background, MP4 with audio.⌛Countdown Video MakerCreate countdown timer videos online: digital, flip clock, ring, big numbers or film leader, up to 60 minutes, with beeps, green screen or transparent WebM.🎻Lyric Video MakerMake lyric and karaoke videos online: import LRC or SRT or tap-sync lyrics, word-by-word fill, scrolling lyrics, bouncing ball, cover art, MP4 with your song.🤏Video Zoom & PanAdd zoom and pan effects to video online: drag a box to set keyframes, eased transitions, punch-in, slow push-in and Ken Burns presets, 9:16 or 1:1, audio kept.🈯Bilingual subtitlesFree bilingual subtitle merger: pair two SRT / VTT / ASS files by timing into one two-line subtitle, or split a bilingual file back into two. Runs in-browser.
📐Math Tools109 tools
View all →📈Graphing CalculatorFree online function graphing calculator: type sin(x), x^2 or 1/x and see the curve at once, with several functions, parametric and polar curves, PNG export.🧮Scientific CalculatorFree online scientific calculator: type 2*(3+4)^2, sin(pi/6) or log(8,2) and see the answer as you type, with degrees or radians and a history list.🟰Equation SolverFree online equation solver: enter coefficients for linear, quadratic (with discriminant, vertex and complex roots) and cubic equations, plus 2×2 systems.½Fraction CalculatorFree online fraction calculator: add, subtract, multiply and divide fractions with automatic reduction, plus fraction ↔ decimal with repeating digits.％Percentage CalculatorFree online percentage calculator: X% of Y, X as a percent of Y, increase and decrease, a value after a percentage change and the original behind it.🔢Prime FactorizationFree online prime factorization: factor an integer with exponents, list every divisor and their sum, test primality with neighbouring primes, or list a range.🔗GCD and LCMFree online GCD and LCM calculator: works with two or more integers, says whether they are coprime, shows each prime factorization and every Euclidean step.📊Statistics CalculatorFree online statistics calculator: paste a data set for the mean, median, mode, range, quartiles, variance, standard deviation, standard error and outliers.🎯CombinationsFree online combination and permutation calculator: exact C(n,r), P(n,r) and n! with big integers, plus repetition variants and the total number of subsets.🔲Matrix CalculatorFree online matrix calculator: add, subtract and multiply matrices up to 8×8, transpose, and compute the determinant, inverse, matrix power and rank.📏Unit ConverterFree online unit converter: length, area, volume, weight, temperature, time, speed, data, pressure, energy and angle — one value converts every unit at once.🎲Random NumbersFree online random number generator: integers or decimals in any range, with no-repeats and sorting, list shuffling and dice, from a cryptographic source.🏛️Roman NumeralsFree online Roman numeral converter: a number to its Roman numeral or back, with validation of standard notation, a symbol-by-symbol breakdown and a table.🈶Number to WordsFree online number to words converter: English words, English currency amounts, Chinese numerals and the financial uppercase form used on invoices.📐Geometry CalculatorFree online geometry calculator: area and perimeter of circles, triangles, polygons and more, plus volume and surface area of solids, with the formulas shown.🔺Triangle SolverFree online triangle solver: SSS, SAS, ASA, AAS and SSA inputs give every side and angle plus the area, perimeter, heights, circumradius and inradius.🔗Sequence CalculatorFree online sequence calculator: nth term, sum of n terms, mean and infinite sum for arithmetic and geometric sequences, plus exact big-integer Fibonacci.⚖️Ratio CalculatorFree online ratio calculator: solve a:b = c:x, reduce decimal ratios to whole numbers, divide a total in a given ratio, and scale sizes by ratio.🌀Complex NumbersFree online complex number calculator: arithmetic on a+bi, powers and nth roots by De Moivre, with modulus, argument, conjugate and polar form for each result.🔬Scientific NotationFree online scientific notation converter: switch between plain numbers and a×10ⁿ, accept 3.5e6, and get engineering notation with SI prefixes and rounding.∫Derivative & IntegralFree online calculus calculator: first and second derivative at a point with the tangent line, or a definite integral by adaptive Simpson with an error bound.🎰Probability DistributionsFree online probability calculator: z-scores and cumulative normal probabilities, P(X=k) and P(X≤k) for binomial and Poisson, plus the mean and variance.📐TrigonometryFree online trigonometry calculator: sin, cos, tan, cot, sec and csc from degrees or radians, inverse functions, DMS conversion and a special-angle table.⚖️Average CalculatorFree online average calculator: arithmetic mean, median, mode, geometric and harmonic mean and RMS in one pass, plus weighted averages for grades and GPAs.💰Interest CalculatorFree online interest calculator: compound interest at any frequency with the effective annual rate, simple interest, monthly savings growth and loan payments.🧭Coordinate GeometryFree online coordinate geometry calculator: distance, midpoint, slope, line equations, point-to-line distance with the foot, triangle centres and polar form.➡️Vector CalculatorFree online vector calculator for 2D and 3D: addition, scalar multiples, dot and cross products, magnitude, angle, unit vector and projections, with checks.🧮Polynomial CalculatorFree online polynomial calculator: type x^3-2x^2-5x+6 for all real and complex roots, factoring, the derivative and antiderivative, plus long division.🔵Set OperationsFree online set calculator: union, intersection, differences and symmetric difference of two groups, with subset and disjoint checks and Jaccard similarity.≤Inequality SolverFree online inequality solver: linear, quadratic and absolute-value inequalities with the answer in set and interval notation, a number line and the reasoning.🧩System of EquationsFree online linear system calculator: fill in the augmented matrix for 2 to 6 unknowns and get the RREF, ranks and the unique, empty or general solution.📉Linear RegressionFree online linear regression and curve fitting: paste x and y columns for the least-squares line, r, R², residuals, predictions and quadratic or cubic fits.㏒Logarithm CalculatorFree online logarithm calculator: log_b(x) for any base with ln, lg and log₂ alongside and the change-of-base working, plus b^x and exponential equations.🎓GPA CalculatorFree online GPA calculator: enter credits and grades for a GPA on the 4.0 scale, US letters, WES bands or a 5-point scale, with a target GPA planner.🎯Significant Figures CalculatorFree online sig fig calculator: count significant figures digit by digit, round to N sig figs or decimals with six rounding modes, and compute by sig fig rules.🔢Sudoku SolverFree online sudoku solver and generator: solve any 9×9 grid in milliseconds, flag invalid or multi-solution puzzles, get single-based hints and candidates.🔣Truth Table GeneratorFree online truth table generator: enter a Boolean or propositional expression for the full table, tautology check, canonical DNF/CNF and Quine–McCluskey.🥚Conic SectionsFree online conic section calculator: from Ax²+Bxy+Cy²+Dx+Ey+F=0 identify the curve and get the standard form, centre, foci, eccentricity and asymptotes.🔐Number TheoryFree online number theory tools: modular exponentiation, modular inverses and Bézout coefficients, the Chinese remainder theorem and Euler's totient φ(n).🧾China Income Tax Calculator (IIT)Free China individual income tax calculator: monthly gross to take-home with social insurance, 2023 deductions, cumulative withholding and annual bonus options.➗Long Division CalculatorFree long division calculator that shows the work: the bracket layout with every divide–multiply–subtract step, remainders, decimals and repeating bars.🏠Mortgage CalculatorFree mortgage calculator: monthly payment, fixed-payment vs equal-principal, total interest, taxes and insurance, extra payments and a yearly schedule as CSV.📝Math Worksheet GeneratorFree printable math worksheet generator for kids: addition and subtraction within 10 to 1000, times tables, division and mixed operations, with an answer key.🏔️3D Surface PlotterFree online 3D surface plotter: type z = f(x, y) and drag to rotate a height-coloured surface — solid, wireframe or contour, several at once, with PNG export.🎲Probability SimulatorFree online probability simulator: coin flips, d4-d20 dice, weighted spinners and urn draws over a million trials, with live histograms and a chi-square test.📏Geometry SketchpadFree online geometry sketchpad: construct points, lines, circles and polygons, drag a free point and watch dependents update, with automatic measurements.∑Taylor SeriesFree online Taylor series calculator: exact coefficients for f(x) at centre a up to order 20, as fractions, with truncation error and a plot against f.🔬Confidence Intervals & TestsFree online statistical inference: confidence intervals for means and proportions, one- and two-sample tests with the statistic, df, p-value and decision.λEigenvaluesFree online eigenvalue calculator: 2×2 and 3×3 matrices — characteristic polynomial, eigenvalues (complex too), eigenvectors, trace and diagonalizability.🎲Bayes’ TheoremFree online Bayes calculator: enter a prior and likelihood (or prevalence, sensitivity, specificity) for the posterior, PPV, NPV and a natural frequency table.🔺Pascal’s TriangleFree online Pascal's triangle tool: generate any number of rows, highlight one for the full (a+b)ⁿ expansion and row sum, and look up any C(n, k) exactly.🛍️Discount CalculatorFree discount calculator: sale price after % off and stacked discounts, spend-and-save deals, deal and unit price comparison, margin, markup, sales tax, tips.→Limit CalculatorFree limit calculator: lim x→a and x→±∞, left- and right-hand limits, 0/0, ∞/∞ and 1^∞ forms by series expansion; spots limits that do not exist.🪜Matrix Step-by-StepStep-by-step matrix calculator: Gauss-Jordan elimination to RREF showing every row operation, plus determinant, inverse, rank and Ax = b in exact fractions.⏲️Time CalculatorFree time calculator: add or subtract hours, minutes and seconds, time between two clock times (even overnight), timesheet totals and decimal hours.∠Angle Converter & Unit CircleConvert degrees ↔ radians (exact, as π/6 or 3π/4) ↔ DMS ↔ gradians ↔ turns, find coterminal and reference angles, and drag an interactive unit circle.🔭Function AnalyzerAnalyze f(x): domain, range, even/odd, period, zeros, monotonic intervals, extrema, concavity, inflection points and asymptotes, with a sign chart and graph.⚡Mental Math PracticeTimed math facts drills for kids: +, −, × and ÷ in 60-second sprint, 20-question or endless mode, with instant feedback, mistake review and personal bests.✖️Multiplication TableInteractive multiplication chart up to 12×12 or 20×20 with row and column highlighting, hide-the-answers practice, a times tables quiz, printing and PNG export.💯Big Number CalculatorArbitrary-precision calculator: exact + − × ÷, 2^1000, 1000!, n choose k, Fibonacci, modular power, GCD/LCM, integer roots, primality and base conversion.⅓Decimal to Fraction ConverterConvert terminating and repeating decimals (0.1(6), 0.[142857], 0.1666…) to fractions with steps, and fractions or percents to decimals with the repetend shown.√Radical Simplifier & CalculatorSimplify square, cube and nth roots (√72 = 6√2, ∛54 = 3∛2) with steps, rationalize denominators, add and multiply radicals, and get roots to 1000 digits.🗾Scale CalculatorMap distance ↔ real distance for any scale, find the scale from two lengths, 1:24, 1:64 and HO 1:87 model sizes, drawing scales, print DPI and area scale.✒️Bézier Curve EditorFree online Bézier curve tool: pen out anchors and handles to join degree 3, 4 or 5 segments into any shape, morph between shapes, export SVG or PNG.∑LaTeX Equation EditorFree online LaTeX equation editor with live preview, a symbol palette and common formulas. Export transparent PNG or SVG, or copy MathML to paste into Word.∂Derivative CalculatorSymbolic derivative calculator with steps: product, quotient, chain and power rules, log differentiation, higher-order and partial derivatives, point values.🗳️Box Plot MakerBox and whisker plots from pasted columns: Tukey, TI-84, Excel INC/EXC or Minitab quartiles, 1.5×IQR and 3×IQR outliers, mean, notches, PNG/SVG export.🪢Graph Theory Algorithm VisualizerDraw a graph, step through BFS, DFS, Dijkstra, Bellman-Ford, Floyd–Warshall, Prim, Kruskal, topological sort, SCCs, bipartite check, Euler paths and max flow.🏭Linear Programming SolverSolve linear programs typed naturally: every simplex tableau with the pivot (two-phase or Big M), graphical method, integer programs and shadow prices.⛰️Standard Normal Table (Z Table)Interactive z table with left, right, mean-to-z and central areas, shaded charts and inverse lookup, plus t, chi-square and F critical value tables.💵China Salary Calculator (Take-Home Pay)China take-home pay calculator: editable city social insurance and housing fund rates, special deductions, monthly IIT, bonus tax, employer cost, net-to-gross.∿Fourier Series & FFT VisualizerFourier series coefficients and animated partial sums for square, sawtooth, triangle or any function (Gibbs), draw-your-own epicycles and FFT spectra.∮Integral Calculator (Step by Step)Step-by-step integral calculator: substitution, by parts, partial fractions, trig powers, completing the square. Every answer is checked by differentiation.💹IRR & NPV CalculatorInvestment calculator: NPV, IRR (detects multiple IRRs), MIRR, XNPV/XIRR on real dates, payback, discounted payback and PI. Matches Excel.🌪️Differential Equation SolverODE tool: slope fields with click-to-trace solutions (RK4/RK45), Euler vs RK4 errors, phase portraits with equilibrium types, and 2nd-order linear ODEs.👥Sample Size & Power CalculatorSample size and power: survey proportions and means, two proportions, two-sample and paired t-tests (matches G*Power), A/B test size and duration.🔑Classical Cipher LabEncode and decode Caesar/ROT13, Vigenère (with Kasiski auto-crack), Playfair, rail fence, affine, Bacon and substitution ciphers, plus an Enigma I simulator.🐚Fractal ExplorerZoom into the Mandelbrot set, Julia sets, Burning Ship, Tricorn and Newton fractals with multithreaded rendering, plus L-systems and the Barnsley fern.♟️Game Theory CalculatorEnter a two-player payoff matrix to find pure and mixed Nash equilibria with exact fractions, eliminate dominated strategies and solve zero-sum games.🐸Markov Chain CalculatorEnter a transition matrix with exact fractions to get the state diagram, n-step matrix Pⁿ, stationary distribution, classification and absorbing-chain results.♠️24 GamePlay the 24 game online with timer, hints and scoring, or solve any 3–6 numbers for 24 (or any target) and see every distinct solution with duplicates removed.📿Online AbacusFree online abacus: soroban (1/4) or suanpan (2/5). Move beads, set any number, watch step-by-step addition and subtraction, and practise flash anzan.🕒Learn to Tell TimeInteractive teaching clock: drag linked hands, see the time in words (quarter past three), work out elapsed time, take quizzes and print clock worksheets.🍕Fraction VisualizerSee fractions as pies, bars and number lines: equivalent fractions, comparing, adding unlike fractions, mixed numbers, simplifying and printable worksheets.🥛Ksp CalculatorFree solubility product calculator with 80 Ksp values at 25 °C: Ksp to molar solubility, the common-ion effect, Q vs Ksp precipitation and hydroxide pH.🧊Colligative Properties CalculatorFree colligative properties calculator: freezing point depression, boiling point elevation, osmotic pressure and Raoult's law, with Kf/Kb and molar mass.⏳Chemical Kinetics CalculatorFree chemical kinetics calculator: reaction orders and k with units by initial rates, zero, first and second-order rate laws, and Ea from the Arrhenius plot.🌡️Calorimetry & Specific Heat CalculatorFree calorimetry calculator: solve q = mcΔT with a specific heat table, find the final temperature of mixtures, get ΔH from coffee-cup and bomb calorimetry.🕸️SMILES Molecule ViewerFree online SMILES viewer: draw a 2D skeletal structure and get the formula, molar and exact mass, unsaturation, rings, H-bond counts and a Lipinski check.📶Isotope Pattern CalculatorFree isotope pattern calculator: enter a formula, pick M, [M+H]+, [M+Na]+ or [M−H]− and get monoisotopic m/z, average mass and the isotope distribution.💎Unit Cells & Crystal StructuresInteractive 3D unit cells (SC, BCC, FCC, HCP, NaCl, CsCl, ZnS, diamond, perovskite) with atoms per cell, coordination number, packing efficiency and density.🌠Light Energy & Atomic SpectraConvert wavelength, frequency and photon energy (eV, J, kJ/mol), compute hydrogen spectral lines, photoelectric stopping potential and de Broglie wavelength.🔬Beer–Lambert & Calibration CurveFree Beer-Lambert calculator: solve A = εbc for any variable, convert absorbance and %T, and fit a calibration curve with R², unknowns, 95% CI and LOD/LOQ.🧩Ionic Compound Formula & NamingWrite ionic formulas from cation and anion by criss-cross, name compounds from formulas and find formulas from names, with acids, hydrates and a quiz.📛IUPAC Name GeneratorName organic compounds from SMILES: IUPAC 2013 and traditional names, highlighted parent chain and step-by-step reasoning. Also name-to-structure and a quiz.🪞Isomer GeneratorList every structural isomer of a formula like C5H12, C4H10O or C3H6Cl2, with drawings, IUPAC names, SMILES, class counts and stereoisomer totals.🔀Molecular Orbital DiagramMO diagrams for H₂–Ne₂, O₂²⁻, N₂⁺, CO, NO, CN⁻ and HF with Hund’s-rule filling: MO configuration, bond order, unpaired electrons, magnetism and HOMO/LUMO.♻️Born–Haber Cycle CalculatorBorn–Haber cycle for NaCl, MgO, CaF₂, Al₂O₃ and more: built-in data, lattice energy or any unknown via Hess’s law, a scaled diagram and Kapustinskii comparison.🫧Net Ionic Equation CalculatorFree net ionic equation calculator: it balances the equation, splits strong electrolytes by solubility rules, cancels spectator ions and checks the charge.〰️IR Spectroscopy TableFree interactive IR correlation table: 60+ functional group bands with range, intensity and shape on a 4000–400 cm⁻¹ chart; enter peaks to identify groups.🧲¹H NMR Spectrum SimulatorSimulate ¹H NMR spectra at 60–600 MHz from shifts, integrals and J values: splitting trees, multiplicity (t, q, dd, dt), journal peak lists and a shift table.🧫Peptide & Protein CalculatorPeptide calculator: formula, monoisotopic and average mass, pI with charge vs pH curve, extinction coefficient, GRAVY, ESI m/z and DNA-to-protein translation.🎳Central Limit Theorem SimulatorProbability simulations: an animated Galton board vs binomial and normal curves, the central limit theorem, law of large numbers and Monte Carlo π.🎇Complex Function Plotter (Domain Coloring)Plot complex functions f(z) by domain coloring: argument as hue, modulus contours, zeros, poles and singularities, with a Riemann sphere view and zoom.▱Linear Transformation VisualizerEnter a 2×2 or 3×3 matrix and watch the grid rotate, scale, shear, reflect or project, with basis vectors, determinant, eigenvectors, inverse and composition.🧊Polyhedra ViewerRotate the 5 Platonic and 13 Archimedean solids, prisms and pyramids in 3D: truncation, duals, Euler’s formula, area and volume, unfolding and printable nets.🥧Chi-Square & ANOVA CalculatorChi-square goodness of fit and independence (Yates, Fisher exact, Cramér’s V), one-way and two-way ANOVA, Tukey HSD, Kruskal–Wallis and Levene’s test.🔨Matrix Decomposition CalculatorStep-by-step LU with pivoting in exact fractions, Cholesky, QR (Gram–Schmidt or Householder) and SVD with rank, condition number and low-rank approximation.🏝️FIRE CalculatorFind your FIRE number and years to financial independence from income, spending and real returns, with Monte Carlo success rates, Coast FI and Barista FI.
🧪Chemistry Tools68 tools
View all →🎯Significant Figures CalculatorFree online sig fig calculator: count significant figures digit by digit, round to N sig figs or decimals with six rounding modes, and compute by sig fig rules.⚗️Chemical Equation BalancerBalance chemical equations by the algebraic method: smallest whole-number coefficients, brackets, hydrates, ionic charges, electrons, atom and charge checks.🧫Molar Mass CalculatorMolar mass of any formula with IUPAC atomic weights: brackets and hydrates, mass percent of each element, grams ↔ moles ↔ particles and solution molarity.⚛️Interactive Periodic TableInteractive periodic table of all 118 elements: colour by category, block, electronegativity, atomic mass, phase or melting point; search and click for details.🧪pH CalculatorFree pH calculator for strong and weak acids and bases, polyprotic acids, salts and buffers, with an exact charge-balance solution and species plots.🫗Titration CurveFree acid-base titration curve simulator: exact curves for strong, weak and polyprotic acids and bases, equivalence-point pH, the jump and indicator picks.🎈Gas Law CalculatorFree gas law calculator: solve PV=nRT for any variable, combined gas laws, gas density, Dalton's partial pressures, gas over water and van der Waals Z.🧴Solution & Dilution CalculatorFree dilution calculator: solve C1V1=C2V2, convert molarity, % w/w, ppm and molality, mix solutions, plan serial dilutions and dilute stock acids.🍶Stoichiometry & Limiting ReagentBalances the equation, finds the limiting reactant from grams, moles, gas volume or molarity, and gives theoretical yield, excess and percent yield with steps.🔎Empirical & Molecular FormulaFind the empirical and molecular formula from mass percent, element masses or combustion data (CO₂, H₂O, N₂), with a whole-number ratio search and full working.🪐Electron Configuration CalculatorFree electron configuration calculator for any element or ion (Fe3+, O2-): full and noble-gas notation, an orbital diagram, unpaired electrons and shells.🧬VSEPR Molecular GeometryFree VSEPR calculator: enter SF4, NH4+ or SO4^2- for the steric number, lone pairs, AXE notation, electron and molecular geometry, angles and hybridization.🔥Reaction enthalpy & Gibbs energyFree ΔH, ΔS and ΔG calculator: type an equation, it balances it and looks up enthalpies of formation, then gives K, crossover temperature and spontaneity.☯️Chemical equilibrium (ICE)Free equilibrium calculator: enter a reaction, K and initial concentrations for the ICE table, exact concentrations, Q vs K and the 5% rule check.🔋Cell Potential & Nernst CalculatorStandard reduction potential table with cell reaction, notation, E°cell, ΔG° and K, plus Nernst equation, concentration cells and Faraday electrolysis.🔆Oxidation Number CalculatorOxidation numbers for any formula or ion with step-by-step rules, plus redox equation analysis: oxidizing and reducing agents and electrons transferred.☢️Half-Life CalculatorSolve radioactive decay for any unknown with 30+ isotopes: decay constant, activity in Bq and Ci, carbon-14 dating and first-order kinetics.🥛Ksp CalculatorFree solubility product calculator with 80 Ksp values at 25 °C: Ksp to molar solubility, the common-ion effect, Q vs Ksp precipitation and hydroxide pH.🧊Colligative Properties CalculatorFree colligative properties calculator: freezing point depression, boiling point elevation, osmotic pressure and Raoult's law, with Kf/Kb and molar mass.⏳Chemical Kinetics CalculatorFree chemical kinetics calculator: reaction orders and k with units by initial rates, zero, first and second-order rate laws, and Ea from the Arrhenius plot.🌡️Calorimetry & Specific Heat CalculatorFree calorimetry calculator: solve q = mcΔT with a specific heat table, find the final temperature of mixtures, get ΔH from coffee-cup and bomb calorimetry.🕸️SMILES Molecule ViewerFree online SMILES viewer: draw a 2D skeletal structure and get the formula, molar and exact mass, unsaturation, rings, H-bond counts and a Lipinski check.📶Isotope Pattern CalculatorFree isotope pattern calculator: enter a formula, pick M, [M+H]+, [M+Na]+ or [M−H]− and get monoisotopic m/z, average mass and the isotope distribution.💎Unit Cells & Crystal StructuresInteractive 3D unit cells (SC, BCC, FCC, HCP, NaCl, CsCl, ZnS, diamond, perovskite) with atoms per cell, coordination number, packing efficiency and density.🌠Light Energy & Atomic SpectraConvert wavelength, frequency and photon energy (eV, J, kJ/mol), compute hydrogen spectral lines, photoelectric stopping potential and de Broglie wavelength.🔬Beer–Lambert & Calibration CurveFree Beer-Lambert calculator: solve A = εbc for any variable, convert absorbance and %T, and fit a calibration curve with R², unknowns, 95% CI and LOD/LOQ.🧩Ionic Compound Formula & NamingWrite ionic formulas from cation and anion by criss-cross, name compounds from formulas and find formulas from names, with acids, hydrates and a quiz.📛IUPAC Name GeneratorName organic compounds from SMILES: IUPAC 2013 and traditional names, highlighted parent chain and step-by-step reasoning. Also name-to-structure and a quiz.🪞Isomer GeneratorList every structural isomer of a formula like C5H12, C4H10O or C3H6Cl2, with drawings, IUPAC names, SMILES, class counts and stereoisomer totals.🔀Molecular Orbital DiagramMO diagrams for H₂–Ne₂, O₂²⁻, N₂⁺, CO, NO, CN⁻ and HF with Hund’s-rule filling: MO configuration, bond order, unpaired electrons, magnetism and HOMO/LUMO.♻️Born–Haber Cycle CalculatorBorn–Haber cycle for NaCl, MgO, CaF₂, Al₂O₃ and more: built-in data, lattice energy or any unknown via Hess’s law, a scaled diagram and Kapustinskii comparison.🫧Net Ionic Equation CalculatorFree net ionic equation calculator: it balances the equation, splits strong electrolytes by solubility rules, cancels spectator ions and checks the charge.〰️IR Spectroscopy TableFree interactive IR correlation table: 60+ functional group bands with range, intensity and shape on a 4000–400 cm⁻¹ chart; enter peaks to identify groups.🧲¹H NMR Spectrum SimulatorSimulate ¹H NMR spectra at 60–600 MHz from shifts, integrals and J values: splitting trees, multiplicity (t, q, dd, dt), journal peak lists and a shift table.🧫Peptide & Protein CalculatorPeptide calculator: formula, monoisotopic and average mass, pI with charge vs pH curve, extinction coefficient, GRAVY, ESI m/z and DNA-to-protein translation.⚖️Redox Equation BalancerBalance redox equations step by step: half-reaction method in acidic, basic or neutral solution, or the oxidation-number method, with atom and charge checks.🔵Lewis Structure GeneratorDraw Lewis structures and electron-dot formulas online, with valence electrons, formal charges, resonance, expanded octets, radicals and ionic compounds.🧯Buffer Preparation CalculatorBuffer recipe calculator: enter pH, concentration, volume and temperature to get grams of each reagent or mL of HCl/NaOH, with activity correction.📈Solubility CurvesInteractive solubility curves for KNO₃, NaCl, NH₄Cl and 11 more: read values, find intersections, and calculate saturated mass fraction and crystal yields.🧻Chromatography CalculatorFree chromatography calculator: drag a TLC plate for Rf, get k, selectivity, resolution, plate number and Purnell, simulate a chromatogram and plot Van Deemter.📏Lab Replicate StatisticsFree analytical chemistry statistics: paste replicates to get mean, SD, RSD and confidence interval, run Dixon's Q, Grubbs, t-tests and the F-test.🎴Periodic Table QuizFree periodic table quiz: symbols, names, positions, atomic numbers, groups, periods and oxidation states, with a timed mode and a mastery heat map.➰Polymer Molecular Weight CalculatorFree polymer calculator: Mn, Mw, Mz, Mv and dispersity from a distribution, degree of polymerization, Carothers equation, Flory distribution and Mark–Houwink.🧊3D Molecule ViewerFree 3D molecule viewer: turn SMILES into a 3D model, rotate and zoom, ball-and-stick or space-filling, measure bond angles and dihedrals, export XYZ or MOL.💎EDTA titration & water hardnessFree EDTA titration calculator: αY(H), conditional constant, minimum pH, Ringbom curve, pM titration curve, end-point error and water hardness.📉Redox & precipitation titration curvesFree redox titration curve calculator: equivalence potential, jump range and indicator choice for Ce⁴⁺, KMnO₄, dichromate and iodine, plus pAg curves.🧮Titrimetric & Gravimetric CalculatorFree analytical chemistry calculator: standardize titrants with KHP or Na₂CO₃, compute direct, back and indirect titrations, titer and gravimetric factors.🔍Ion Tests & Qualitative AnalysisFree qualitative analysis reference: tests for common cations, anions and gases with equations, an unknown-solution simulator and a test planner.🧬Enzyme Kinetics CalculatorPaste [S] and rate data to fit Michaelis–Menten by nonlinear regression: Km, Vmax with 95% CI, kcat, Lineweaver–Burk comparison and inhibition Ki.🔌Conductivity CalculatorCalculate cell constants, molar conductivity, Λm° by Kohlrausch's law, transport numbers and weak acid Ka, plus conductometric titration curves and TDS.🧷Bond Polarity CalculatorGet ΔEN, bond type, percent ionic character and the bond dipole for any two elements, decide molecular polarity by 3D vector sum, and compute dipole moments.📊Periodic TrendsChart ionization energy, electronegativity, atomic radius, electron affinity and melting/boiling points vs atomic number for Z 1–86, with Slater's-rules Zeff.📚Chemical Equations LibraryFree searchable library of 386 balanced chemical equations from school to general chemistry, with conditions, observations, ionic equations and flash cards.🥇Metal Activity SeriesFree reactivity series tool: pick a metal and a solution to see whether displacement happens, with balanced equations, an E° chart and a mixture simulator.🔋Electrode reactions (cells & electrolysis)Write electrode half-equations: electrolysis by discharge order, lead–acid and Li-ion batteries, fuel cells in any electrolyte, and corrosion of iron.🌈Acid–base indicatorsAcid–base indicator chart: see 15 indicators' colours at any pH, pick the right indicator for a titration, and compute the In⁻ fraction from pKIn.🗺️Organic Reactions MapInteractive functional-group map: reagents, conditions, balanced equations and pitfalls for each reaction, tests for each class, and a shortest-route finder.🔷Point Group FinderFind a molecule's point group: symmetry elements detected from 3D coordinates, the flowchart path, a 3D model with axes and mirror planes, and character tables.🟣Crystal Field Theory CalculatorFree crystal field calculator: draw the d-orbital splitting diagram and get high/low spin, CFSE, unpaired electrons, magnetic moment and absorbed colour.🕸️Coordination Compound Naming & IsomersFree coordination compound tool: get IUPAC and Chinese names, oxidation state, coordination number, geometry, isomers and 18-electron count from a formula.⚛️Atomic Structure & Average Atomic MassGet protons, neutrons and electrons from 23Na+ or Cl-37, average atomic mass and isotope abundances, isotope/allotrope checks and shell diagrams.🟪UV–Vis λmax (Woodward–Fieser)Estimate UV λmax of dienes and enones with Woodward–Fieser rules: count substituents, ring residues and exocyclic bonds, add solvent; plus Fieser–Kuhn.🤝Conjugate acid–base pairsFree conjugate acid–base pair finder: label Brønsted acids, bases and conjugate pairs in any reaction, predict products and equilibrium direction from pKa.💦Salt hydrolysis & solution balancesFree salt hydrolysis calculator: exact pH and every species' concentration for salts and mixtures, ion ranking, and verified charge, mass and proton balances.⛓️Reaction Mechanism SimulatorSimulate reaction mechanisms from elementary steps: concentration–time curves, steady-state and pre-equilibrium rate laws checked against the full kinetics.🍾Vapor–Liquid Equilibrium & DistillationAntoine vapor pressure and boiling point for 20 liquids, Raoult's law T-x-y diagrams, McCabe-Thiele stages, minimum reflux, Fenske and Rayleigh distillation.🧪Common Solvent PropertiesBoiling point, density, refractive index, dielectric constant and polarity index of 36 lab solvents, plus a miscibility chart and solvent picker.🫙Liquid–Liquid Extraction CalculatorFree extraction calculator: single vs multiple extraction recovery from KD, distribution ratio vs pH, acid–base separation, countercurrent and layer order.
⚛️Physics Tools196 tools
View all →📏Unit ConverterFree online unit converter: length, area, volume, weight, temperature, time, speed, data, pressure, energy and angle — one value converts every unit at once.➡️Vector CalculatorFree online vector calculator for 2D and 3D: addition, scalar multiples, dot and cross products, magnitude, angle, unit vector and projections, with checks.🎯Significant Figures CalculatorFree online sig fig calculator: count significant figures digit by digit, round to N sig figs or decimals with six rounding modes, and compute by sig fig rules.🔉Tone GeneratorFree online tone generator: sine, square, sawtooth and triangle waves from 1 to 20,000 Hz, a note picker, sweeps, white/pink/brown noise and a WAV download.🌌Audio SpectrogramFree online spectrogram generator: see time, frequency and level from a Hann-windowed STFT, with FFT size, log axis, dB range and colour maps. Exports PNG.📢Decibel MeterFree online decibel meter: measure noise with your mic in real time, A/C/Z weighting, fast/slow response, min/max/average/Leq, 60-second graph and calibration.🧲Physics Formula CalculatorPhysics formulas solved with steps: SUVAT, projectiles, Newton’s laws, inclines, energy, Ohm’s law, resistors, RC, buoyancy, waves, lenses, gravity.∿Fourier Series & FFT VisualizerFourier series coefficients and animated partial sums for square, sawtooth, triangle or any function (Gibbs), draw-your-own epicycles and FFT spectra.🌪️Differential Equation SolverODE tool: slope fields with click-to-trace solutions (RK4/RK45), Euler vs RK4 errors, phase portraits with equilibrium types, and 2nd-order linear ODEs.🎈Gas Law CalculatorFree gas law calculator: solve PV=nRT for any variable, combined gas laws, gas density, Dalton's partial pressures, gas over water and van der Waals Z.☢️Half-Life CalculatorSolve radioactive decay for any unknown with 30+ isotopes: decay constant, activity in Bq and Ci, carbon-14 dating and first-order kinetics.🌡️Calorimetry & Specific Heat CalculatorFree calorimetry calculator: solve q = mcΔT with a specific heat table, find the final temperature of mixtures, get ΔH from coffee-cup and bomb calorimetry.💎Unit Cells & Crystal StructuresInteractive 3D unit cells (SC, BCC, FCC, HCP, NaCl, CsCl, ZnS, diamond, perovskite) with atoms per cell, coordination number, packing efficiency and density.🌠Light Energy & Atomic SpectraConvert wavelength, frequency and photon energy (eV, J, kJ/mol), compute hydrogen spectral lines, photoelectric stopping potential and de Broglie wavelength.🎯Projectile Motion Simulator (with Air Resistance)Animated projectile simulator: set speed, angle, height and gravity (Earth, Moon, Mars, Jupiter), add air drag (RK4), compare paths and find the best angle.🕰️Pendulum & Double Pendulum SimulatorSimulate a nonlinear pendulum (RK4) beside its small-angle twin: exact period, damping, phase space and energy plots, plus a chaotic double pendulum.🎱Collision Simulator (Momentum & Energy)Simulate 1D cart collisions with any masses, velocities and restitution e, see momentum and KE before and after, plus 2D billiard collisions.🪐Orbit & Gravity SimulatorDrag a satellite's velocity to get circular, elliptic or hyperbolic orbits with live orbital elements, Kepler's equal areas, N-body demos and Δv tools.🔍Lens & Mirror Ray DiagramInteractive ray diagrams for converging and diverging lenses and concave and convex mirrors: drag the object to see image position, size and magnification.🌈Refraction & Total Internal Reflection SimulatorDrag a light ray through water, glass or diamond: refraction angle, Fresnel reflectance, critical angle, Brewster angle, prism dispersion and apparent depth.🌊Wave Superposition & Standing WavesInteractive wave simulator: superpose traveling waves, see standing waves on strings and pipes with nodes and harmonics, hear beats, and explore a ripple tank.🚑Doppler Effect SimulatorDoppler effect calculator with animation: moving source and observer, Mach cone and sonic boom, relativistic redshift, radar speed guns and pass-by audio.⚡Electric Field & Potential SimulatorDrag point charges and watch electric field lines and equipotentials update live. Probe E and V anywhere, compute Coulomb forces and launch a test charge.🟫Resistor Color Code CalculatorResistor color code calculator for 4, 5 and 6 bands: value, tolerance and tempco; find bands for any value snapped to E12/E24/E96; decode SMD codes like 472.🔌RC / RL / RLC Circuit SimulatorSimulate RC charging and discharging, RL current and RLC step response with τ marks, plus resonance, Q, bandwidth, filter cutoff, Bode plots and live phasors.🚀Special Relativity Calculator & Spacetime DiagramLorentz factor, time dilation and length contraction with a rocket animation, relativistic energy, velocity addition, twin paradox and a Minkowski diagram.🔥Blackbody Radiation & Planck's Law VisualizerPlot Planck blackbody curves for several temperatures with Wien peaks, σT⁴ power, visible fraction, blackbody colour and the Rayleigh–Jeans comparison.🌀Spring Oscillator & ResonanceAnimated spring-mass-damper with driving force: live x(t), damping regime with ω₀, ζ and Q, resonance curves, and coupled normal modes with beats.🧲Magnetic Field SimulatorDrag current-carrying wires and bar magnets to see field lines, compass needles and |B|. Exact loop and solenoid fields, on-axis B(z) and forces between wires.☄️Charged Particle in E & B FieldsElectrons, protons or alphas in any uniform E and B in 3D: gyroradius, period, pitch and E×B drift, plus a velocity selector, mass spectrometer and cyclotron.🔄Electromagnetic Induction & GeneratorMove a magnet through a coil and watch flux, EMF and the galvanometer obey Lenz's law, plus an AC generator, a rod on rails and a transformer.💡DC Circuit Builder & SolverBuild DC circuits on a grid with batteries, resistors, bulbs, switches and meters. Nodal analysis gives every voltage, current and power, plus KCL/KVL.🌗Diffraction, Interference & PolarizationFree wave-optics simulator: slit and grating patterns in white light, Airy disks and the Rayleigh limit, thin-film colours, Newton's rings and Malus's law.🌡️Heat Conduction SimulatorSimulate heat conduction: animated 1D rod (Crank–Nicolson) with real materials, paintable 2D plate, composite wall U-value calculator and Newton cooling fit.💧Fluid Mechanics Simulator (Bernoulli, Buoyancy, Pipe Flow)Interactive fluid mechanics: drag a pipe to see Bernoulli at work, Venturi meter, Torricelli tank draining, buoyancy, Pascal press and Reynolds number.🛞Moment of Inertia & Rotational DynamicsMoment of inertia for rods, disks, spheres, plates and composites with the parallel-axis theorem; rolling race, spinning skater, Atwood machine.🎡Circular Motion & Centripetal Force SimulatorAnimated circular motion: velocity and centripetal vectors, cut the string, centrifugal force, banked curves, coaster loops, conical pendulum.🔬Quantum Mechanics Simulator (Schrödinger Equation)Solve the 1D Schrödinger equation online: energy levels and wavefunctions for wells, oscillators or a drawn potential, plus tunneling wave packets and T(E).♨️Heat Engine Cycles & PV DiagramsInteractive PV and TS diagrams for Carnot, Otto, Diesel, Brayton, Stirling and custom cycles. Drag states, see Q, W, ΔU, ΔS per step, efficiency and COP.🫧Kinetic Theory of Gases SimulatorWatch hundreds of colliding molecules: speed histogram vs Maxwell–Boltzmann, pressure from wall impacts, mean free path, piston heating, effusion and mixing.⚛️Nuclear Binding Energy, Fission & FusionBinding energy per nucleon from AME2020 masses, mass defect and SEMF terms for any nuclide, and Q-values for fusion, fission and decay vs TNT and coal.⚙️Simple Machines Simulator (Levers, Pulleys, Gears)Drag a lever’s fulcrum, lift loads with pulleys, mesh gear trains and bike gears, and compare inclines, screw jacks and wedges: force and efficiency.🏋️Free-Body Diagrams & Force VectorsInteractive free-body diagrams: add and resolve force vectors, solve a block on an incline with friction and a pulley, rope tensions and the ladder problem.🏗️Beam Shear & Bending Moment CalculatorFree beam calculator: simple, overhanging and cantilever beams with point, distributed and triangular loads. Reactions, shear and moment diagrams, deflection.🔋Capacitor SimulatorSlide a dielectric into a parallel-plate capacitor and see C, Q, V, E and energy change. Plus cylindrical and spherical capacitors and series-parallel networks.🔀Logic Circuit SimulatorBuild digital logic circuits in your browser: gates, flip-flops, switches, LEDs and 7-segment displays, with live simulation, truth tables and timing diagrams.🔊Acoustics Calculator (RT60, Room Modes, Decibels)Room acoustics online: Sabine & Eyring RT60 from room size and materials, room modes, dB addition, distance loss, A-weighting, noise dose, speed of sound.🎨Color of Light Simulator (Additive & Subtractive)Mix red, green and blue spotlights, stack cyan, magenta and yellow filters, and see objects under sodium, LED or tungsten light via spectra and CIE 1931.👁️Eye Optics Simulator (Myopia, Hyperopia, Astigmatism)Reduced-eye ray diagrams for myopia, hyperopia, astigmatism and presbyopia, a blurred eye chart, far/near points, glasses vs contacts power, Rx reader.🚀Rocket Equation & Launch SimulatorRocket equation calculator: get Δv from Isp and mass ratio, design multi-stage rockets, compare Δv budgets, and simulate a gravity-turn launch with Max-Q.🌌Lagrange PointsLagrange point simulator: find L1–L5 for Sun–Earth, Earth–Moon and Sun–Jupiter, map the effective potential and zero-velocity curves, launch test particles.🦋Chaos & Strange AttractorsExplore chaos: logistic map cobwebs and zoomable bifurcation diagram, Lyapunov exponent, Feigenbaum constant, 3D Lorenz attractor and Poincaré sections.📏Error Propagation & Uncertainty CalculatorPropagate uncertainty through any formula: enter values ± errors to get the result, partial derivatives, error budget, Monte Carlo check and weighted line fit.🥁Chladni Patterns & Drum ModesChladni pattern simulator: sweep the frequency and watch sand gather on nodal lines, play the tone, animate drum Bessel modes and mix degenerate modes.📖Physical Constants Table (CODATA 2022)Searchable CODATA 2022 physical constants: c, h, electron mass, fine-structure constant and 100+ more with uncertainties. Copy as LaTeX or code, convert units.📐Dimensional Analysis ToolCheck if a physics equation is dimensionally consistent, simplify units like kg·m²/s³/A to V, find dimensionless groups with Buckingham π, see Planck units.🧊Ising Model SimulatorLive 2D Ising model: Metropolis and Wolff Monte Carlo, energy, magnetisation, specific heat, susceptibility, T scans vs Onsager's solution, hysteresis.🐾Brownian Motion & Diffusion SimulatorSimulate Brownian motion: thousands of random walkers, Langevin dynamics, MSD slope fits, Lévy flights and subdiffusion, Stokes–Einstein D and Fick's law.⭐H-R Diagram & Stellar EvolutionInteractive Hertzsprung-Russell diagram with 80+ famous stars in blackbody colours, constant-radius lines, a main-sequence calculator and evolution tracks.🌠Cosmology CalculatorΛCDM cosmology calculator: from H₀, Ωm, ΩΛ and redshift get age, lookback time and comoving, luminosity and angular-diameter distances, with a(t) and H(z).🕳️Black Holes & Gravitational LensingBlack hole calculator: Schwarzschild radius, photon sphere, ISCO, shadow size, Hawking temperature, evaporation time and tides, with orbit and lensing demos.☀️Solar System SimulatorSolar System orrery: planet positions for any date 1800–2050 from JPL Keplerian elements, with distances, elongations, opposition dates and a scale model.📡Electromagnetic Waves & PolarizationAnimated 3D EM plane wave with E and B, intensity and radiation pressure calculator, Jones-matrix polarization, Poincaré sphere and an EM spectrum explorer.🔆Semiconductors & PN JunctionsPN junction band diagrams for Si, Ge and GaAs with built-in potential and depletion width, diode I–V with series resistance, LED colours and solar cells.🔺Op-Amp Circuit CalculatorOp-amp calculator with schematics: inverting, non-inverting, summing, difference, instrumentation, Sallen–Key, Schmitt trigger, plus Bode plots and E24 design.🧱Materials Properties & Stress–Strain CurvesCompare stress–strain curves of 15 materials with an animated tensile test: E, yield, UTS, toughness. Axial load, thermal stress, bimetal strip and Ashby chart.🫗Surface Tension & CapillaritySurface tension calculator: animated Jurin capillary rise, Laplace pressure of drops and soap bubbles, drop shapes, Stokes' law settling and a floating needle.☢️Radiation Dose & Shielding CalculatorLearn radiation dose: convert Gy, Sv, rem, R, Bq and Ci, ICRP 103 effective dose, a log-scale dose chart, point-source dose rates, HVL and alpha/beta range.🪀Gyroscope & Spinning Top Simulator3D heavy symmetric top simulator: RK4 rigid-body motion with precession and nutation (cusps, waves, loops), sleeping-top threshold and a bicycle-wheel gyro.🌊Tides & Roche Limit ExplorerExplore tides: tidal force field and bulge, spring and neap tides, M2/S2/K1/O1 tide curves, an animated Roche-limit breakup and lunar recession vs day length.⚙️DC Motor Simulator & Torque–Speed CurvesInteractive DC motor: animated commutator and Lorentz force, torque ripple, speed, current and efficiency, torque–speed curves and start-up inrush current.🔌AC Power & Power Factor CalculatorAC power calculator: P, Q, S and power factor with waveforms, PF-correction capacitors, star/delta three-phase with neutral current, energy bills and THD.🟠Gauss’s Law Visualizer & Field CalculatorVisualize Gauss’s law for spheres, shells, coaxial cables, planes and plates: drag the Gaussian surface, see enclosed charge and flux, and plot E(r) and V(r).〰️Wave Pulse on a String: Reflection & TransmissionPulses on a string: inverted or upright reflection at a junction, measured r and t vs theory, fixed, free and absorbing ends, colliding pulses, standing waves.🔦Laser physics simulatorLaser simulator: animated 2/3/4-level atoms show inversion; rate equations give threshold, L–I curve, spiking and Q-switching; cavity modes and Gaussian beams.🧬Particle physics & the Standard ModelInteractive Standard Model chart (PDG 2024 masses), quark hadron builder, conservation-law checker for reactions, two-body decay and invariant-mass calculator.🌍Earth's Energy Balance & Greenhouse Effect SimulatorPlanetary energy balance lab: effective temperature, N-layer greenhouse model, global energy budget diagram, CO₂ forcing, two-box warming and spectra.🎲Entropy & microstatesInteractive statistical entropy: coin macrostates, Einstein solids and temperature, free expansion ΔS = Nk ln 2, Boltzmann levels and Maxwell's demon.🛹Energy Skate ParkSkate park energy simulator: draw your own track, try loop, ski jump and double-well presets, add friction and drag, and watch live KE, PE and heat bars.⛵Relative Motion & Reference FramesRelative velocity simulator: river crossing (min time vs min drift), aircraft wind triangle, rain seen from a moving car, and closest approach of two ships.📉Motion Graphs (x-t, v-t, a-t)Build a motion by dragging the v-t graph and see synced x-t and a-t graphs with tangent slope and area, plus a graph-matching game and translation drills.🎐Normal Modes & Lattice VibrationsNormal modes of a mass-spring chain (1–30 masses; fixed, free or periodic ends): mode animation, superposition, dispersion, diatomic band gap and wave packets.🧶Fiber Optics SimulatorFiber optics simulator: trace TIR rays by dragging the launch angle, find NA and acceptance angle, V-number and modes, bend loss, link budget and dispersion.🔭Telescope CalculatorTelescope calculator: magnification, true field, exit pupil, resolution, limiting magnitude, a to-scale eyepiece view and astrophoto sampling.⚛️Hydrogen Atom OrbitalsPlot exact hydrogen wavefunctions ψnlm up to n = 7: phase cross-sections with nodes, a 3D electron cloud, radial r²R², levels and sloshing superpositions.🩻X-ray Physics: Tube Spectrum, Bragg & ComptonX-ray tube spectra with Kα/Kβ lines and filters, Moseley’s law, Bragg diffraction with powder patterns, and Compton scattering with Klein–Nishina plots.🌀Coriolis Effect & Foucault PendulumSee the Coriolis force on a turntable from both frames, compute shell and falling-object deflection, cyclones, inertial circles and Foucault precession.🚗Vehicle Dynamics: Braking, Crashes & CorneringCar physics: stopping distance by speed, reaction time and road with animation, crash g-forces, cornering and rollover limits, 0–100 time and energy use.⚽Magnus Effect: Spinning Ball TrajectoriesSimulate spinning balls in 3D with drag and Magnus lift: banana kick, curveball, topspin and golf presets, no-spin comparison and spinning-cylinder flow.🏔️Atmosphere & Altitude CalculatorISA 1976 standard atmosphere: temperature, pressure, density and sound speed at any altitude, altitude from pressure, boiling point, oxygen, dew point.🌊Water Waves & Ocean WavesWater waves: phase and group speed from wavelength or period and depth, orbit animation, wave power, tsunami travel time, shoaling, breaking, wind seas.🌋Seismic Waves & Earthquake MagnitudeAnimate P, S, Rayleigh and Love waves, locate an epicentre from S−P times, compute Richter and moment magnitude and energy, and trace rays through the Earth.🌈Rainbow Formation SimulatorTrace light through a raindrop, get the 42° primary and 51° secondary bows from water's dispersion, render a double rainbow, see polarization and halos.🌅Light Scattering & Sky ColourRayleigh scattering simulator: render the sky from noon to twilight, see why it is blue not violet, why clouds are white and how skylight is polarized.☀️Solar Position, Irradiance & PV Yield CalculatorFind solar elevation, azimuth, sunrise, sunset and the sun path for any place and date, clear-sky irradiance on a tilted panel, optimal tilt and rough PV yield.🌬️Wind Power Calculator - Betz Limit & Turbine EnergyCalculate wind power ½ρAv³, see the Betz limit derived on an animated actuator disk, design a turbine power curve and estimate annual energy from Weibull winds.🔋Battery Capacity, Runtime & Pack CalculatorConvert mAh to Wh, work out battery runtime, C-rate and charge time, see why power banks quote 3.7 V, build nSmP packs and check the 100 Wh airline limit.🧲Magnetic Materials & HysteresisSimulate B–H loops and losses for silicon steel, ferrite and NdFeB, watch domain avalanches, compare dia-, para- and ferromagnets, estimate magnet pull.🎸String Instrument Physics: Tension & Fret CalculatorString tension for guitar, bass, ukulele and violin sets, printable fret tables, how the pluck point shapes harmonics, and piano inharmonicity.🧊Phase diagrams & phase transitionsInteractive P–T phase diagrams for water, CO₂ and nitrogen: drag a state point, animate pressure cooking and freeze-drying, try Clausius–Clapeyron and vdW.🎈Static Electricity & LightningTriboelectric series, electroscope induction animation, charge sharing between spheres, Paschen breakdown and spark length, corona at points, thunder distance.📶Smith Chart & Impedance MatchingInteractive Smith chart: click or type a load to get Γ, VSWR and return loss, rotate along a line, design stub and L-network matches, sweep RLC loads.📡Antenna Patterns & ArraysExact dipole/monopole patterns, directivity and radiation resistance; phased-array steering with Chebyshev tapers; Friis link budget; antenna length by band.✈️Flight Physics Simulator (Lift, Stall & Aircraft Performance)Interactive flight physics: NACA airfoils with potential-flow animation, lift curve and stall, stall speed, glide range, power curve, turn g and climb forces.🪂Skydiving Simulator (Terminal Velocity & Opening Shock)Skydiving simulator with air density varying by altitude, body positions, canopy opening and transonic drag. Recreates Baumgartner; compares terminal speeds.🎈Hot-Air & Helium Balloon Lift CalculatorBalloon physics calculator: hot-air lift, payload and equilibrium altitude with an ascent animation, lifting gases, helium balloons per person, burst altitude.🎢G-Force & Apparent Weight CalculatorG-force calculator: elevator scale readings incl. free fall, coaster loop and airtime g, space-station artificial gravity, human tolerance chart and g from Δv.🏃Human biomechanicsPhysics of the body: jump height to takeoff speed, force and power; Froude number and walk–run speed; cycling power and climb time; MET calories; biceps force.🪐Exoplanet Detection SimulatorTransit light curves with limb darkening and noise, radial-velocity curves and Doppler shifts, and Kopparapu habitable zones with planet temperatures.🌑Solar & Lunar EclipsesSee why eclipses are total or annular with real Sun, Moon and Earth sizes: shadow cones, magnitude, lunar eclipse durations, Saros series and a 2026–2035 table.🌔Moon Phase CalculatorMoon phase for any date and city: illumination, age, distance, a correctly oriented Moon image, a monthly phase calendar, full/new moon times and moonrise.⚖️Your Weight on Other PlanetsEnter your weight in kg, lb or jin to see it on the Moon, Mars, Jupiter, Pluto or a neutron star, plus jump height, fall time, throw range and escape velocity.🫧Thin-Film Interference & InterferometersSpectrally computed soap bubble and oil film colours, a draining soap film, AR coating designer, Newton's rings radius fit and a Michelson interferometer.💡Photoelectric Effect LabVirtual photoelectric lab: choose a metal, wavelength, intensity and bias, watch photoelectrons and the I–V curve, and fit Planck's constant.📷Camera Optics: Depth of Field & ExposurePhotography optics calculator: depth of field, hyperfocal distance, field of view, exposure triangle, motion blur, NPF star rule, diffraction limit and bokeh.🤿Scuba Diving Physics CalculatorDive physics online: pressure and Boyle's law animation, SAC and rule of thirds, nitrox MOD and best mix, buoyancy and weighting, ZHL-16C no-deco demo.🌀Gravitational Wave Simulator (Binary Inspiral & Chirp)Enter two masses and a distance to get chirp mass, time to merger and the strain waveform h(t), see a ring of particles stretch, and hear the chirp.🦇Sonar, Radar & EcholocationAnimated echo ranging and range resolution, bat Doppler, ocean sound speed and ray bending, radar equation range and PPI scope, speed radar, ultrasound depth.🧭Earth’s Magnetic Field & Aurora (Dipole, Declination, Van Allen Belts)Tilted-dipole model of Earth’s field: declination, inclination and strength anywhere, magnetosphere and Van Allen belts, and where Kp lets you see aurora.🧲Superconductivity SimulatorResistance drop at T_c for real superconductors, Meissner field lines, type I/II phase diagram and vortex lattice, London depth, flux-pinning levitation, MRI.🛰️Gravity Assist & Interplanetary Transfer SimulatorSimulate a gravity assist: set v∞ and periapsis to see the turn angle and Sun-frame speed gain, then get Hohmann Δv, flight time and launch windows.🔌Wire Size & Voltage Drop CalculatorVoltage drop for DC, 1- and 3-phase; smallest cable size by drop limit and ampacity (mm², AWG), loss cost, breaker hint, 12 V solar and LED strips.🌡️Thermal Expansion CalculatorLinear, area and volume expansion, expansion joints, rail stress and buckling, bimetallic thermostat, shrink fits, liquids and the 4 °C water anomaly.❄️Heat Pump & Air Conditioner CalculatorAnimated heat pump / AC cycle with P–h diagram, Carnot vs real COP, heat pump vs electric vs gas heating cost, AC sizing in W, BTU/h and HP.🛝Brachistochrone Race (Cycloid vs Line, Arc, Parabola)Drag the endpoints and race beads down a line, circular arc, cycloid, parabola and your own curve, add friction, and explore the tautochrone and Snell analogy.⚛️Nuclear Fission Reactor SimulatorNeutron chain reaction and criticality, fission energy vs fuels, six-factor formula, point kinetics with delayed neutrons, decay heat and PWR efficiency.🕶️Polarization & Birefringence SimulatorJones-calculus optical bench: drag polarizers and wave plates, see the E-field ellipse and Poincaré sphere; Brewster angle, calcite, interference colors, LCDs.🔬Microscope Resolution & Imaging CalculatorMicroscope calculator: Abbe and Rayleigh resolution from NA and wavelength, Airy-disk demo, useful magnification, camera sampling, phase contrast, STED, EM.🌊Ripple Tank SimulatorReal-time 2D ripple tank: place sources, draw walls and slits; single and double slit, gratings, refraction, lens focus, standing waves and Mach cones.🎺Wind Instruments & Resonance Tube CalculatorOpen, closed and conical pipe resonances with end correction and standing-wave animation; flute vs clarinet, tone holes, resonance tube, bottles, organ pipes.💫Neutron Stars & PulsarsCompare white dwarfs, neutron stars and black holes, see light bending, watch and hear a pulsar, get age and B-field from P and Ṗ, and distance from DM.📍How GPS WorksDrag satellites and a receiver to see how pseudoranges solve position and clock error and why 4 satellites are needed; constellation, DOP, relativity and RTK.🗼Space ElevatorSpace elevator physics: net acceleration vs altitude, taper ratio by material, climb time and energy, release orbits, counterweight, Moon and Mars.☄️Atmospheric Reentry SimulatorSimulate spacecraft reentry: set speed, entry angle, ballistic coefficient and L/D to get altitude, speed, g-load and heat flux, plus the entry corridor.☀️Nuclear fusion & tokamaksInteractive fusion explorer: D-T, D-D, p-B11 reactivity, Gamow peak, Lawson triple product and ignition, tokamak and laser implosion animations, Q gain.🧠MRI physics simulatorInteractive MRI physics: Larmor precession, RF flip, T1/T2 relaxation, TR/TE weighting on a synthetic brain, spin-echo animation, k-space FFT reconstruction.💧Hydropower calculatorHydropower calculator: P = ηρgQH, turbine selection, penstock loss and economic diameter, annual energy from flow duration, pumped storage, dam pressure.🏭Power grid simulatorPower grid physics: high-voltage line loss, AC vs HVDC breakeven, duck-curve dispatch, frequency drop after a trip with load shedding, three-phase, PF.🌬️Virtual Wind Tunnel (2D Flow Simulation)Live 2D lattice Boltzmann wind tunnel: vortex streets, airfoils, cars and buildings. Draw obstacles, view vorticity, get drag, lift and Strouhal number.🌉Truss Solver (2D Truss Analysis)2D truss calculator: draw nodes, members, supports and loads. Get member forces, reactions and deflection, check stability and buckling, see joint steps.✨Live Sky ChartFree live sky chart for any city or latitude and time: 1,267 bright stars, 51 constellations, the Sun, Moon and planets, and rise, transit and set times.🕰️Sundial DesignerDesign horizontal, vertical or equatorial sundials for your latitude: hour-line angles, gnomon angle, printable SVG, equation of time and clock conversion.☄️Asteroid Impact SimulatorAsteroid impact calculator (Collins et al. 2005): energy in Mt TNT, airburst or crater, crater size, fireball, earthquake, blast radius and tsunami.🔋Wireless charging & induction cooktopsCompute coil mutual inductance and coupling k, simulate resonant wireless power and frequency splitting, align a Qi phone, see why hobs need iron pans.♨️How a microwave oven heatsSimulate cavity standing waves, hot spots and turntable heating, measure light speed with chocolate, see dielectric loss and penetration depth, metal sparks.⚡Tesla coilDesign a spark-gap Tesla coil: primary and secondary inductance, top-load capacitance, resonance and tap point, energy transfer, voltage and spark length.🔊Loudspeakers, enclosures & noise cancellingEnter Thiele–Small parameters, design sealed and ported boxes with response, impedance and excursion plots, port length and air speed, crossovers and ANC.🏰Trebuchet SimulatorCounterweight trebuchet physics: Lagrangian RK4 model of ground slide, sling swing and release, drag flight, range, efficiency, sweeps and onager comparison.🏹Archery Physics CalculatorBow physics: draw-force curve to stored energy and arrow speed for longbow, recurve and compound bows, KE, momentum, trajectory, sight marks, drift, spine.🚲Bicycle Physics CalculatorBike physics: gear ratios and speed per cadence, power vs speed with rolling, aero and gradient, climb times and W/kg, Whipple self-stability, braking limits.⛵Sailing Physics: Apparent Wind, Sail Forces & PolarsHow sailing upwind works: draggable apparent-wind triangle, sail lift and drag split into drive and heel, keel leeway, polar diagram, VMG, heel, hull speed.🏢Earthquake-resistant buildings & dampersSimulate a multi-storey building in an earthquake: mode shapes, Newmark time history, response spectrum, base isolation and tuned mass dampers (Taipei 101).🌀Harmonograph & Lissajous figuresHarmonograph simulator: 2–4 damped pendulums draw colourful curves; set ratios, detune and damping, export PNG/SVG. Also Lissajous figures and interval tones.🥣Non-Newtonian fluidsExplore non-Newtonian fluids: power-law, Bingham, H-B and Carreau curves with presets, plug flow in pipes, oobleck stiffening, ketchup yield and thixotropy.📏Vernier Caliper & Micrometer ReadingInteractive vernier caliper and micrometer: drag the slider or thimble, zoom in, see each reading explained with zero error, and practise with instant marking.🎞️Ticker Tape Timer AnalysisSimulate a ticker-tape timer: generate tapes, measure counting points, get speeds and acceleration by successive differences, plot v–t and cut-tape charts.🎛️Meter Conversion & Electrical MeasurementsConvert a galvanometer to an ammeter or voltmeter, explore the ohmmeter scale, voltmeter–ammeter errors, EMF and internal r, bridge and half-deflection.📦Conveyor Belt & Block-on-Board ModelsConveyor-belt and block-on-board friction problems: phase-by-phase forces, common speed, v–t graphs, relative sliding and heat, with practice.📟Virtual OscilloscopeOnline dual-channel oscilloscope simulator: volts/div, time/div, coupling, trigger level and slope, X-Y Lissajous mode, built-in function generator and cursors.🔺Transistor Amplifier & Switch SimulatorNPN BJT simulator: output curves, load line, draggable Q-point and operating regions, CE amplifier bias, gain and clipping, plus BJT and MOSFET switch design.⏱️555 Timer Calculator & Simulator555 timer calculator with an animated internal diagram synced to the capacitor and output waveforms: astable, monostable and a standard-value parts picker.📶Sampling Theorem & Aliasing SimulatorInteractive sampling theorem demo: sinc and zero-order-hold reconstruction, alias frequency and folding, spectral images, wagon-wheel effect, quantization.🧭Spin & the Stern–Gerlach experimentChain Stern–Gerlach analysers at any angle, fire atoms and compare counts with cos²(Δθ/2). Classical vs quantum screens, spin 1, Bloch spheres, CHSH test.🎲Quantum statistics & heat capacity of solidsCompare Maxwell-Boltzmann, Fermi-Dirac, Bose-Einstein occupation with animated particles; get Fermi energy, BEC transition temperature, Debye heat capacity.〰️Pendulum wavePendulum wave simulator: N pendulums with L = g(Γ/2π(N₀+k))², 3D animation of snakes, rows and realignment, large-angle effects and a DIY length table.🌀Typhoon & Hurricane PhysicsHolland wind profile from central pressure and radius of max winds: wind radii, Saffir-Simpson and China typhoon grades, potential intensity, surge, wind load.🌋Volcano Eruption PhysicsEruption column height from mass eruption rate with VEI, magma viscosity and bubble growth to fragmentation, volcanic bomb trajectories with drag, lava speed.📻Radio Propagation & the IonosphereChapman-layer ionosphere and plasma frequency, sky-wave ray tracing with hops and skip zone, MUF, skip distance, D-layer absorption, radio horizon, path loss.🏠Household Circuits & Electrical SafetyInteractive house wiring: plug in appliances to trip the breaker, read the energy meter and bill, use a test pen, compare shocks and RCDs, with quizzes.🎚️Circuit Dynamics AnalyzerMove a rheostat or change an LDR or thermistor and watch every meter in a circuit with internal resistance update; output power, capacitors, faults, practice.🛤️Rail Induction ModelsConducting rods on rails in a magnetic field: coasting, constant force or power, capacitor, incline and two-rod models with v–t, i–t, energy and analysis.🧲Hall Effect & Crossed-Field DevicesHall effect animation with Hall voltage, carrier type and density, plus velocity selector, MHD generator, flowmeter, mass spectrometer, cyclotron and practice.🎯Momentum Conservation ModelsAnimated classic momentum problems: bullet and block, block on board, spring pair, person and boat, ball on an arc slot, explosions, with energy bars.🧪Trapped Gas Columns & PistonsGas law problems: mercury column in a tilted tube, U-tube with added mercury, piston with stops or springs, two chambers, with p–V graphs and first law.📈Wave and Vibration GraphsSynchronised wave (y–x) and vibration (y–t) graphs with direction rules, multiple-solution problems, two-source interference, standing waves and quizzes.🧊Heating Curves & Specific HeatHeating curve of ice to steam with a particle model, crystalline vs amorphous solids, specific heat, mixing, fuel efficiency, a four-stroke engine and quizzes.⚖️Cavendish Experiment SimulatorVirtual Cavendish torsion balance: damped oscillation, optical-lever readings, turning-point analysis, G with corrections, weighing the Earth, Coulomb balance.💧Millikan Oil Drop ExperimentVirtual Millikan oil drop lab: balance a drop, time its fall in the eyepiece, get radius and charge with Cunningham correction, then find e from a histogram.🎯Rutherford Scattering SimulatorRutherford gold foil experiment: alpha hyperbolas vs impact parameter, detector counts vs the Rutherford formula and Thomson model, and nuclear size limits.🔦Franck–Hertz Experiment SimulatorFranck–Hertz tube simulation with mercury or neon: inelastic collisions, anode current vs accelerating voltage, peak spacing, excitation energy and wavelength.💨Speed of Light HistoryInteractive history of measuring c: Galileo's lanterns, Rømer's Io eclipses, aberration, Fizeau's wheel, Foucault's mirror, Michelson and Michelson–Morley.🌈Holography SimulatorSimulate holography: place points, record fringes, refocus via FFT angular spectrum, compare in-line vs off-axis, cut the plate, draw a Fourier hologram.🎡Vertical Circular MotionCircular-motion exam models: string vs rod critical speeds, leaving the circle, loop-the-loop, turntable, conical pendulum, banked curves and bridges.🛰️Satellite Orbits & Binary StarsGravitation exam models: orbit comparison, GM = gR², geostationary orbit, cosmic speeds, orbit transfer, satellite chase, binary stars, mass and density.🔗Connected Bodies & Instant AccelerationConnected bodies with Newton’s 2nd law: strings, pushes, pulleys, stacked-block slipping, spring vs string instant acceleration, elevator readings.🚗Vehicle Start-up (Power vs Acceleration)Car start-up exam model: constant power vs constant acceleration, v–t, a–t, P–t and F–t graphs, top speed, work–energy distance, uphill driving.📺Charged Particle Acceleration & DeflectionCharged particles in electric fields: accelerate with qU₁ = ½mv₀², deflect by y = U₂L²/(4U₁d), find the screen spot, plus CRT sweep, AC plates and practice.⭕Charged Particles in a Bounded Magnetic FieldCharged particles in bounded magnetic fields: edge, strip, rectangle, circle, triangle, step-by-step centre finding, dynamic circles and focusing.🌐Combined Electric, Magnetic & Gravitational FieldsCharged particles in combined fields: exact paths in E, B and gravity (line, circle, cycloid), equivalent gravity on a string, and multi-region analysis.⛵Solar Sail & Radiation PressureSolar sail simulator: radiation pressure I/c vs 2I/c, oblique force, lightness number, spiral orbits at the 35° optimum and the Starshot laser sail.🧱Pressure & Communicating VesselsMiddle-school pressure lab: bricks on a sponge, a U-tube gauge probe, vessel shapes, communicating vessels, ship lock, hydraulics, Torricelli and practice.⚖️Density LabVirtual density lab: level a beam balance and read the rider, read a measuring cylinder, six density methods, error analysis, m-V graphs and quizzes.🧲Electromagnets & RelaysMiddle-school electromagnetism: Oersted's experiment, solenoid poles and field lines, electromagnet strength, relay alarms, electric bell, motor and generator.🔌Ohm’s Law & Lamp Power LabVirtual school electricity lab: current vs voltage and resistance, measuring resistance and lamp power, with wiring mistakes and faults explained.🪞Reflection & Plane MirrorsInteractive school optics: test the law of reflection, specular vs diffuse reflection, plane mirror images, two mirrors, periscope and pinhole camera.🔍Convex Lens LabVirtual optical bench: move the candle, lens and screen to find a sharp image, measure focal length, learn the lens rules and correct short and long sight.
🧠Productivity93 tools
View all →🧠QiLing MindQiLing Mind is a free online mind map editor: add nodes with Tab/Enter, drag to restructure, import and export XMind and Markdown, export PNG/SVG/PDF.🔐Password GeneratorFree online random password generator: choose length, character sets and look-alike exclusions, generate several at once with a strength meter, all locally.📱QR Code GeneratorFree online QR code generator: turn URLs, text, Wi-Fi or contact cards into QR codes with custom size, colour and error correction. Crisp PNG or vector SVG.🔡Word CounterFree online word counter: live counts of characters with and without spaces, words, CJK characters, lines, paragraphs, sentences, bytes and reading time.🔠Case ConverterFree online case and naming converter: get UPPERCASE, lowercase, Title Case, camelCase, PascalCase, snake_case, kebab-case and CONSTANT_CASE at once.📝Lorem Ipsum GeneratorFree online Lorem Ipsum generator: classic Latin placeholder text or Chinese filler by paragraph, sentence or word, with one-click copy for mockups.↕️Sort & Dedupe TextFree online text tool: sort lines alphabetically or by length, remove duplicate and empty lines, trim whitespace, optionally ignoring case. Runs locally.✍️Sign & Stamp PDFFree online PDF signing tool: drop in a handwritten signature or company stamp, drag it into place on a page preview, adjust size and opacity, then export.📊Barcode GeneratorFree online barcode generator: Code 128 with automatic code sets, EAN-13 with its check digit and Code 39. Adjust size, quiet zone and colours; SVG or PNG.⚖️BMI CalculatorFree online BMI calculator: height and weight give your body mass index, the WHO and Chinese categories, a healthy weight range, plus BMR and daily calories.📅Date CalculatorFree online date calculator: days, weeks, months and workdays between two dates; add or subtract to find a date and its weekday; exact age and next birthday.🎲Random Name PickerFree online random name picker: draw winners with no repeats across rounds, pick students at random, split people into balanced groups or shuffle a list.🧹Text CleanerFree online text cleaner: strip extra spaces and blank lines, rejoin lines broken by a PDF copy, convert full-width ↔ half-width and CJK ↔ Latin punctuation.🔁Find and ReplaceFree online find and replace: several rules applied in order, plain text or regex, case and whole-word options, a live match count and $1 capture groups.🔊Text to SpeechFree text to speech: near-human AI voices run in your browser, unlimited, downloadable as WAV, in English and Chinese. System voices cover many more languages.⏱️Online TimerFree online timer: countdown with presets, alarm and screen flash; stopwatch with laps; Pomodoro 25/5 cycles. Big digits, accurate in background tabs.🌐Time Zone ConverterFree online time zone converter and world clock: pick a time and see it in New York, London, Tokyo, Shanghai or any city, with UTC offsets and DST handled.📊Chart MakerFree online chart maker: paste data from Excel or CSV to build bar, line, area, pie, donut and scatter charts, then download a 2× PNG or an editable SVG.🀄Chinese to PinyinFree online Chinese to pinyin converter: tone marks, numbers or none, initials only, context-aware polyphones, surname readings and ruby annotation.繁Simplified ↔ Traditional ChineseFree online Chinese converter powered by OpenCC: Simplified ↔ Traditional for Taiwan, Hong Kong or OpenCC standard, with optional Taiwan vocabulary.🖋️Signature MakerFree online e-signature tool: photograph a handwritten signature for a clean transparent PNG with paper and shadows removed, or draw one and export PNG or SVG.🗓️Chinese Lunar CalendarFree Chinese lunar calendar for 1900–2100: lunar dates, zodiac, stem-branch years, the 24 solar terms with exact times, festivals and a lunar date converter.📡Morse Code TranslatorFree online Morse code translator: text to Morse and back, played as audio with adjustable WPM and tone, a flashing light, a WAV download, and space-bar keying.🗒️Online NotepadFree online notepad that autosaves in your browser: several notes, search, rename, undo delete, word count, Markdown preview, TXT/MD export and focus mode.⌨️Typing Speed TestFree online typing test: WPM, CPM and accuracy over 30s, 60s, 120s or a full passage, with live error highlighting, a speed chart and personal bests.🎡Spin the WheelFree online spinning wheel: add weighted options, spin with a tick sound, see the history, remove winners, use presets, and share a wheel by link.⏳Days Until / Days SinceFree online days-until and days-since counter: add exams, holidays and anniversaries and see a live count to the second, with repeats and a share link.😀Emoji PickerFree online emoji picker: 1,100+ emoji in nine groups, searchable in English and Chinese — click to copy, pick a skin tone, see code points and shortcodes.🃏FlashcardsFree online flashcards with SM-2 spaced repetition: grade each card Again, Hard, Good or Easy; several decks, CSV and Anki import, saved in your browser.📌Kanban BoardFree online Kanban board: several boards with custom columns, cards with labels, due dates and checklists, drag and drop or keyboard moves, autosaved locally.💸Split BillFree online bill splitter for trips and dinners: add people and expenses, split equally, by share or by amount, and settle with the fewest transfers.🖊️Annotate PDFFree online PDF annotator: highlight, draw, add shapes, arrows, sticky notes and text boxes, then save as editable annotations or flatten them. Runs locally.💴Invoice & Quote GeneratorMake invoices, quotes, receipts and proforma invoices online: line items with discounts and tax, automatic totals, logo and signature, 3 templates, PDF.🛡️Password Strength CheckerTest password strength privately in your browser: entropy and crack time, detects common passwords, keyboard walks, dates and l33t, optional breach check.👔Resume BuilderBuild a resume or CV online: photo, experience, education, skills and custom sections you can reorder, 4 templates, live A4 preview with page breaks, PDF.☁️Word Cloud GeneratorFree word cloud maker: paste text or open a file, word counts with stopword removal, editable frequency table, heart, star or image shapes, PNG and SVG.☑️Create PDF FormMake any PDF fillable: draw text fields, checkboxes, radio buttons, dropdowns, date and signature fields; set names, required flags and tab order. Free, local.🌱Habit TrackerFree habit tracker: daily or weekly goals, one-tap check-ins, current and best streaks, monthly calendar, yearly heatmap, stats, notes and JSON/CSV export.🗣️Speech to TextFree online speech to text: talk into your mic for live transcription in 20+ languages with timestamps, auto punctuation, editing and TXT or SRT export.🎥TeleprompterFree online teleprompter: your script scrolls at your WPM pace. Set font size, spacing and colors, mirror for beam-splitter glass, count down, go full screen.🧑🏫Online WhiteboardFree online whiteboard: infinite canvas, pressure-aware pen, highlighter, eraser, shapes, arrows, text and sticky notes, undo/redo, pages and PNG/SVG export.📆Calendar MakerFree printable calendar maker: a year on one page or a page per month, with holidays, week numbers, events, monthly photos and themes. Print or export PNG.⛓️Flowchart MakerFree flowchart maker: describe nodes and links in plain text (Mermaid flowchart syntax) for an auto-laid-out diagram with shapes and themes. SVG/PNG export.🚧Gantt Chart MakerFree online Gantt chart maker: tasks with dates or durations, progress, milestones and dependencies, working days, drag to reschedule, PNG/SVG/CSV export.▦Online SpreadsheetFree online spreadsheet and CSV editor: SUM, AVERAGE and IF formulas with auto-recalc, sort, filter, find & replace, Excel copy-paste, CSV/TSV/JSON export.🏹Screenshot AnnotatorFree screenshot annotator: paste with Ctrl+V, add arrows, boxes, numbered steps, highlighter and text, pixelate or blur secrets, crop, copy or save PNG/JPG.🏅Certificate MakerMake award certificates in bulk: classic, gold, modern and simple templates, a pasted list of names, {name}/{award} placeholders, seal, PDF or PNG ZIP.🏫Class Timetable MakerMake a class timetable online: Mon–Fri to Mon–Sun, periods with times, auto colors, quick fill, merged double periods, A4 landscape print, PNG, CSV and JSON.🛒Unit Price CalculatorCompare products by unit price: per oz, lb, kg, L, item or sheet, with % off, spend-and-save, second-item discounts and buy-N-get-M deals. Finds the best value.🗞️WeChat Article FormatterTurn Markdown into WeChat Official Account articles: 8 themes, code highlighting, tables, nested lists, links as footnotes, one-click copy that keeps styles.📛Business Card MakerDesign business cards: 9 front/back templates, US, EU, China and Japan sizes, logo, colors, vCard QR code, print-ready PDF with 3 mm bleed and crop marks.📓Handwriting Practice Sheet MakerMake printable handwriting sheets: Chinese tian/mi grids, pinyin grids, manuscript paper, English four-line paper, tracing or model-and-trace, PDF or PNG.🔰Chinese ID Number ValidatorValidate Chinese ID numbers (GB 11643-1999): check digit, birth date, region, gender, age, zodiac; 15-to-18 upgrade; batch check with CSV. Runs locally.✉️Envelope & Address Label PrinterPrint envelopes (DL, C5, C6, US #10, Chinese with postcode boxes) and A4/Letter label sheets (L7160, L7163, L7651, 5160) from CSV with {field} templates.🔮QR Code Art GeneratorFree styled QR code maker for URLs, Wi-Fi, vCards, email, SMS and maps: dot or diamond modules, custom eyes, gradients, logo, PNG/SVG/JPG and a scan check.💺Seating Chart MakerMake classroom, U-shape, round-table or conference seating charts: seeded random, by height, boy–girl, keep-apart/together rules, locks, rotation, print.🗄️Batch File RenamerFree bulk file renamer: find & replace with regex, prefixes, numbering, case, EXIF photo date, extensions. Live preview, conflict checks, ZIP or rename script.🎱Bingo Card GeneratorMake printable bingo cards: 75-ball B-I-N-G-O, UK 90-ball tickets or custom word and emoji bingo, all unique, 1–6 per page, with a call sheet and caller.▤Graph Paper GeneratorMake printable paper: square grid, dot, isometric, hex, polar, log, engineering, music staff, guitar tab, Cornell notes, lined and calligraphy as vector PDF.📒Printable Planner MakerPrintable planner pages: daily, weekly, monthly, year at a glance, habit tracker, to-do, meal plan, budget and reading log, with auto dates for a month or year.🧐Word Search & Crossword MakerMake printable word search and crossword puzzles from your words and clues: diagonal and backwards words, compact numbered crosswords, answer keys, seeds.👯Duplicate Photo FinderFind duplicate and similar photos in your browser: SHA-256 for identical files, perceptual hashes for resized or recompressed copies; keep the best, export CSV.🤔Decision MatrixWeighted decision matrix online: score options against criteria, set weights directly or by AHP pairwise comparison with CR, rank and test sensitivity.🪙Expense TrackerFree private expense tracker: categories, accounts, tags, currencies, monthly budgets, pie, trend and heatmap reports, recurring bills, CSV import. Stays local.🎪Markdown SlidesWrite slides in Markdown: --- splits slides, 9 themes, 16:9 or 4:3, code highlighting, columns, backgrounds, fragments, presenter view, PDF and HTML export.📬PDF Form Mail MergeFill a PDF form from CSV rows: auto-matched fields, checkboxes, radios, dropdowns, CJK text, optional flattening, one PDF per row or combined; export form data.📧Email Signature GeneratorCreate a professional HTML email signature: 8 templates, photo or logo, social icons, CTA banner and disclaimer, table-based for Gmail, Outlook and Apple Mail.💒Invitation & Greeting Card MakerMake invitations and greeting cards for weddings, birthdays, baby showers, parties and holidays: 12 templates, QR codes, one card per guest, PNG or PDF.📙Text AnalyzerAnalyze text in depth: word and character frequency, n-grams, SEO keyword density, Flesch, Fog and SMOG scores, sentence lengths, MTLD and repeated phrases.💡Brain TestsFree quick brain tests: reaction time, sequence, number, verbal and visual memory, aim trainer, chimp test, Stroop test and Schulte tables, with personal bests.🤝Meeting PlannerFind a meeting time across time zones: add cities and working hours, see overlaps on a 24-hour timeline, get best-time picks and export .ics or Google Calendar.👓Reading Speed TestTest your reading speed: original English and Chinese passages at three levels, a comprehension quiz, effective WPM vs. average, plus an RSVP speed reader.📤Rename PDFs by ContentBatch rename PDFs by content: put dates, invoice or order numbers, emails, totals, titles or labelled text into a name pattern; preview clashes.📩Letter & Document TemplatesFree fill-in templates: leave request, receipt, IOU, employment verification, authorization and resignation letters, plus Chinese formats. Print, PDF or copy.🎁Gift LedgerFree private gift ledger: log wedding, shower and birthday gifts received and given, see each person’s balance, get return-gift ideas and print a list.👷Shift Schedule MakerFree shift scheduler: set staff, shifts and daily headcount, then auto-build a fair roster that respects rest and weekly-off rules. Rotations, print, CSV.🗜️ZIP CompressorFree online ZIP tool: pack files or a whole folder into one zip, pick a compression level and optionally protect it with AES-256, all inside your browser.📦Unzip OnlineFree online zip extractor: open a zip with nothing installed, browse and preview what is inside, extract only what you need, use a password, fix garbled names.🔐ZIP PasswordFree online tool to password-protect a zip or strip the password from one you can open: AES-256 or ZipCrypto, with garbled filenames repaired on the way.🗃️RAR / 7Z ExtractorFree online extractor for RAR, 7Z, TAR, TAR.GZ, TAR.XZ, TAR.BZ2, CAB, ISO and more: browse the contents, preview files and extract what you need without WinRAR.🗄️TAR ArchiverFree online tar tool: pack files or a whole folder into .tar or .tar.gz with the folder structure intact, built in your browser and never uploaded.✂️Split / Join FilesFree online file splitter: cut a big file into .001 .002 parts by size or count to fit an attachment limit, and join the parts back together. Runs locally.📊Excel ConverterFree online Excel converter: open an xlsx, read every worksheet and export it as CSV, TSV, JSON, a Markdown table or HTML. Date serial numbers become dates.📝Word ConverterFree online Word converter: read headings, lists, tables, images and footnotes out of a docx and export Markdown, single-file HTML or plain text.📽️PowerPoint ConverterFree online PowerPoint converter: read each slide's title, bullet levels, tables, images and speaker notes out of a pptx and export Markdown, text or notes.📗TXT to EPUBFree online TXT to EPUB converter: chapters are detected to build the table of contents, legacy encodings are repaired, and you can add a cover and author.📖EPUB ConverterFree online EPUB converter: read the whole book in reading order and export Markdown, plain text or a single-file HTML page, or print it to PDF. Parsed locally.🏷️EPUB Metadata EditorFree online EPUB metadata editor: change the title, author, language, publisher, description and subjects, replace the cover and repack a valid EPUB.📡Peer-to-peer sendFree peer-to-peer file transfer: scan one QR code to pair a phone and a computer, then files go straight between them — no upload and no size limit.🧾OFD viewerFree online OFD viewer: open the .ofd files used by Chinese e-invoices and official documents, convert them to searchable PDF or PNG, and extract the text.📱China Phone Number CheckFree checker for Chinese mobile numbers: validate the format, identify the carrier by prefix, flag MVNO, IoT and satellite ranges, and export them as CSV.🗓️ICS Calendar FileFree online ICS generator: build .ics files with times, location, recurrence and alarms for Apple Calendar, Outlook or Google, or read an .ics someone sent you.🔴Seal ExtractorFree online seal extractor: lift a red or blue stamp off a scan into a transparent PNG, dropping paper, tint and specks. Solid colour, auto-trim, runs locally.
💻Developer Tools93 tools
View all →{}JSON FormatterFree online JSON formatter: beautify or minify, validate with the exact line and column of any error, browse a collapsible tree, sort keys and escape strings.🔤Base64 Encode/DecodeFree online Base64 encoder and decoder: UTF-8 safe, optional URL-safe variant, convert text to Base64 and back in real time. Processed locally, never uploaded.🔗URL Encode/DecodeFree online URL encoder and decoder with encodeURIComponent and encodeURI modes. Escapes Chinese, spaces and special characters. Real-time and local, no upload.🎫JWT DecoderFree online JWT decoder: decode the header and payload of a JSON Web Token, show expiry and issued-at times, all locally without uploading the token.🕐Timestamp ConverterFree online Unix timestamp converter: convert timestamps and dates, auto-detect seconds or milliseconds, and show local, UTC, ISO 8601 and relative time.#️⃣Hash / ChecksumFree online hash calculator: SHA-1, SHA-256, SHA-384 and SHA-512 of text or any file through the browser crypto API. Files never leave your device.🆔UUID GeneratorFree online UUID generator: create RFC 4122 UUID v4 in bulk with a cryptographic RNG. Options for uppercase, no hyphens and braces, with one-click copy.🔢Base ConverterFree online number base converter: convert between binary, octal, decimal, hexadecimal and any base 2–36. Uses BigInt for huge integers, computed locally.🔍Regex TesterFree online regular expression tester: match and highlight as you type, list capture groups and support the g/i/m/s/u flags. Runs locally, nothing uploaded.🆚Text DiffFree online text diff tool: compare two texts line by line, highlight added and removed lines, and optionally ignore case and trailing spaces. Runs locally.🎨Color ConverterFree online color converter: convert between HEX, RGB and HSL with a built-in color picker and preview, one-click copy, computed locally in real time.🔣HTML Entity Encode/DecodeFree online HTML entity encoder and decoder: escape < > & " and more to entities or decode them back, with optional non-ASCII conversion. Runs locally.⏰Cron ExpressionFree online cron tool: parse a 5-field cron (min hour dom mon dow), break down each field and predict the next 5 run times in your local zone. Computed locally.📰Markdown PreviewFree online Markdown previewer: render Markdown to a live web preview with GFM, tables and code blocks, copy the generated HTML. Runs locally, no upload.🔐Chmod CalculatorFree online chmod calculator: tick read, write and execute for owner, group and others to convert octal (755) and symbolic (rwxr-xr-x), with setuid and sticky.🌐Subnet CalculatorFree online IPv4 subnet calculator: enter 192.168.1.10/24 for the network, broadcast, host range and count, wildcard mask, binary view and a prefix table.🧾CSV to JSONFree online CSV ⇄ JSON converter: handles quotes, commas and newlines inside fields, auto-detects the delimiter, with a header toggle and type conversion.🚦HTTP Status CodesComplete HTTP status code reference: every 1xx–5xx code with its name and a plain-language explanation, searchable by code, name or keyword.🔷JSON to TypeScriptFree online JSON to TypeScript converter: interfaces or types from JSON, nested objects split into named interfaces, optional fields inferred, Go structs too.📋Markdown Table GeneratorFree online Markdown table generator: edit cells visually, add rows and columns, set per-column alignment, and import from Excel, CSV, TSV or Markdown.🗃️SQL FormatterFree online SQL formatter: beautify SELECT, JOIN, subqueries, CASE and WITH with clause line breaks and indentation, set keyword case, or minify to one line.🈶Unicode ConverterFree online Unicode converter: text to and from \uXXXX, HTML entities, UTF-8 hex bytes, %XX and U+ code points, with correct emoji handling and auto-detection.🧭URL ParserFree online URL parser: split a link into protocol, host, port, path and hash, edit decoded query parameters in a table, rebuild the URL live, export as JSON.🕵️User-Agent ParserFree online User-Agent parser: browser and version, rendering engine, OS, device type and model, and bot detection for Googlebot, Bingbot and GPTBot.🔣Truth Table GeneratorFree online truth table generator: enter a Boolean or propositional expression for the full table, tautology check, canonical DNF/CNF and Quine–McCluskey.🎨CSS FormatterFree online CSS beautifier and minifier: one declaration per line, correct @media, nesting and url() handling, optional property sorting and a byte count.🔀JSON DiffFree online JSON diff: compare two documents ignoring key order, see added, removed and changed paths with old and new values, and export an RFC 6902 patch.🏷️XML FormatterFree online XML formatter: beautify or minify XML, validate it with line and column errors, keep comments and CDATA, and convert XML to JSON and back.📋YAML to JSON ConverterFree online YAML and JSON converter: multi-document YAML, anchors, aliases and merge keys, errors with line and column, plus indent, sorting and folding.🌈CSS Gradient GeneratorFree online CSS gradient generator: build linear, radial and conic gradients visually with draggable stops, an angle dial and presets. Copy CSS or export PNG.🌓CSS Box Shadow GeneratorFree online CSS shadow generator for box-shadow and text-shadow: stack layers with offset, blur, spread and colour, start from presets, copy CSS or Tailwind.🌀curl ConverterFree online curl converter: paste a curl command and get fetch, axios, Node, Python requests, Go, PHP or Java code, plus a parsed view of the request.🔒Text Encryption & DecryptionFree online text encryption: AES-256-GCM or CBC with a password (PBKDF2, OpenSSL-compatible output), raw key + IV mode, RSA-OAEP and HMAC signatures.🗺️JSONPath TesterFree online JSONPath tester: query JSON with $.store.book[*], recursive .., slices and filters, listing every matching path and value, plus a cheat sheet.🏗️HTML FormatterFree online HTML formatter: beautify or minify in one click, keep <pre> and <textarea> intact, format embedded CSS and JSON-LD, with a sandboxed live preview.🔏JWT Generator & SignerFree online JWT generator: edit the header and payload, sign with HS, RS, PS or ES 256/384/512, make RSA / EC key pairs, and verify with exp/nbf checks locally.🎹Keycode FinderFree online JavaScript key event viewer: press a key to see event.key, code, keyCode, location and modifiers, with an on-screen keyboard and a reference table.🧪Mock Data GeneratorFree online mock data generator: define fields and generate up to 10,000 rows of fake names, emails, addresses, dates and IDs, exported as JSON, CSV or SQL.🔌WebSocket TesterFree online WebSocket client: connect to ws:// or wss://, send text, JSON or binary messages, read a filterable log, auto-reconnect, plus an SSE tester.🚫.gitignore GeneratorFree .gitignore generator: combine 40 templates (Node, Python, Java, Go, Rust, Unity, macOS, VS Code…), dedupe, add custom rules, test which paths git ignores.🟨JavaScript FormatterFree online JavaScript formatter: beautify or minify JS, TypeScript, JSX and JSON with 2/4-space or tab indent and line width. Handles regex, templates, ASI.✅JSON Schema Generator & ValidatorGenerate a draft 2020-12 or draft-07 JSON Schema from sample JSON (types, required, nesting, formats) and validate JSON with JSON Pointer error paths. 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