Can I compare scanned PDFs?

Scans have no extractable text, so the text diff will be empty — switch to the visual diff, which compares the pages pixel by pixel and still boxes the changed areas. Or run PDF OCR first to make the scans searchable and then compare the text.

What if the two PDFs have a different number of pages?

Pages are paired by number and any extra pages are marked as “only in A” or “only in B”. If the revision added a cover page at the front, set “Page offset for B” to 1 so the remaining pages line up again.

Why is the visual diff almost entirely red?

Usually the page size changed or the content shifted as a whole (for example one extra line pushes everything down), so nearly every pixel differs. Raise the sensitivity threshold to cut noise, or rely on the text diff.

Are my files uploaded?

No. Text extraction, comparison and rendering all happen locally in your browser, which makes it safe for contracts, bids and other confidential documents.

🔬

🔬Compare PDF - Find Text and Visual Differences Between Two PDFs Online

Reviewing a contract, a thesis revision or a quote, the scariest change is the one nobody told you about. Drop in the original and the revised version: the tool extracts each page’s text with PDF.js and compares it word by word (character by character for Chinese and Japanese), marking additions in green and deletions in red with strikethrough, and summarises which pages changed and how many words were added or removed — jump from one change to the next with a click. When the PDF is a scan without a text layer, or the change is in an image, a table rule or a signature, switch to the visual diff: both pages are rendered at the same width and compared pixel by pixel, with changed regions boxed in red. View them side by side, as a difference overlay, or with a slider that wipes between the two versions, and tune the sensitivity. Different page counts are fine — extra pages are flagged — and if the revision inserted pages at the front you can set a page offset to realign them. Everything runs in your browser, so confidential files never leave your computer.

Free · No sign-up · Runs in your browserLast updated: 2026-10-26

Loading tool...

How to use Compare PDF

1Upload the original PDF (A) and the revised PDF (B)
2If B has extra or missing pages at the front, set the page offset, then click Compare
3Review the change summary, read added and removed words in Text diff, and inspect red-boxed layout changes in Visual diff

FAQ

Can I compare scanned PDFs?: Scans have no extractable text, so the text diff will be empty — switch to the visual diff, which compares the pages pixel by pixel and still boxes the changed areas. Or run PDF OCR first to make the scans searchable and then compare the text.
What if the two PDFs have a different number of pages?: Pages are paired by number and any extra pages are marked as “only in A” or “only in B”. If the revision added a cover page at the front, set “Page offset for B” to 1 so the remaining pages line up again.
Why is the visual diff almost entirely red?: Usually the page size changed or the content shifted as a whole (for example one extra line pushes everything down), so nearly every pixel differs. Raise the sensitivity threshold to cut noise, or rely on the text diff.
Are my files uploaded?: No. Text extraction, comparison and rendering all happen locally in your browser, which makes it safe for contracts, bids and other confidential documents.