# Join Split Files Back Together

Received a file in pieces named .001, .002, .003? Add them all and get the original back, checked against its fingerprint when the .parts.json file came with them. No software to install, on a phone or a computer.

_Source: https://sharelargefilesfree.com/tools/join-files · Updated 2026-09-29_

## How to use it

1. Choose or drop all the parts, and the .parts.json file if you have it.
2. Check the order (it is sorted by part number for you).
3. Press Join files.
4. Save the joined file or send it on with a link.

## Which parts can be joined

- Parts made with [Split file](https://sharelargefilesfree.com/tools/split-file), with or without the checksum file.
- 7-Zip “split to volumes” of a normal file, HJSplit, `split` on Linux and macOS, and other plain byte splits named .001, .002 and so on.
- Not these: multi-part RAR or ZIP archives (.part1.rar, .z01), which have their own format and must be opened with the archive program.

## Verified, or it tells you what is wrong

With the `.parts.json` file, every part is matched by name and size before anything is joined: a missing part or one that stopped downloading halfway is reported by name. After joining, the SHA-256 of the result is compared with the original's. Only a byte-for-byte identical file is given back; if a part is damaged, you are told which one to get again.

Without the checksum file the parts are joined in number order, and the result is as good as the parts you added.

## Big files, small memory

The joined file is assembled from your parts without copying them into memory, so a 2 GB video joins on a phone as easily as on a computer, in your browser, without uploading anything. To check a file against a published hash, use the [file hash checker](https://sharelargefilesfree.com/tools/file-hash-checker).

## Frequently asked questions

### How do I open a .001 file?

A .001 file is the first part of a split file. Add it and all the other parts (.002, .003…) here, press Join files and open the joined file.

### What is the .parts.json file?

A small checksum list made by Split file. Add it with the parts to verify that the joined file is identical to the original.

### One part is missing. Can I still join?

No. Every part is needed; the file would be incomplete. Ask the sender for the missing part.

### Does it work on iPhone?

Yes. Choose all parts from Files, join them and save the result to Files.

### Are my files uploaded?

No. They are joined on your device.