# Split a Large File Online and Join the Parts Back

> Free 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.

- URL: https://qilingtools.com/en/split-file
- Category: Productivity (https://qilingtools.com/en/office)
- Tags: [Merge & Split](https://qilingtools.com/en/tags/split-merge), [Productivity](https://qilingtools.com/en/tags/office)
- Last updated: 2026-10-26
- Price: Free, no sign-up
- Privacy: Runs locally in the browser; files are never uploaded

When a file is too big for chat or an email attachment, cut it into smaller parts, send them separately, and put them back together on the other side. Splitting only slices bytes — nothing is re-encoded, and the joined file is identical to the original. All of it happens in your browser.

## How to use

1. Choose "Split", drop the big file in, and pick a part size (say 25 MB) or a number of parts
2. Use "Save all to a folder" to write every part at once
3. On the other side, switch to "Join parts", drop all the parts in, and download the restored file

## Features

- Split by part size or by number of parts
- Named .001, .002 — the 7-Zip and HJSplit convention
- Parts are sorted automatically and missing ones are flagged
- Also prints the cat / copy commands for joining in a terminal

## FAQ

### Do I still need the original file?

No. The parts concatenated in order are the original, byte for byte. Just make sure you have every part — joining with one missing produces a corrupt file, which is why this tool checks that the numbering is continuous.

### How does the recipient join them without this site?

Splitting is plain byte slicing, so the built-in shell does it: cat file.001 file.002 > file on macOS or Linux, copy /b file.001+file.002 file on Windows. The page prints the ready-made command for you to copy.

### Does splitting make the file smaller?

No, the parts add up to exactly the original size. Compress first with ZIP or tar.gz if you need less data, then split the archive.

### What size can it handle?

Splitting uses Blob slices and never reads the contents, so it is instant at any size. Joining has the browser assemble the result before download, so past a few GB you may hit memory limits — use the command line for those.

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