Compared · checked 2026-10-24
The best free diff tools to compare files
A diff tool shows what changed between two versions of a file. These four are free to start with. Here is what each one compares and where it runs, from its own pages.
We make Compare, one of the tools on this page. Every fact about the other tools comes from their own pages, linked under each one, as they read on 2026-10-24. Prices and features change: check each site before you choose.
How we compared them
- Free, with no account
- What it compares: texts, folders, PDFs, pictures, tables
- Where it runs and whether files stay on your device
- Reports and patches you can keep
At a glance
| Tool | Price | Runs on | Compares | Licence |
|---|---|---|---|---|
| Compare ours | Free | Any modern browser | Texts and code, JSON, CSV, PDFs, pictures | MIT |
| Diffchecker | Free text compare; Pro and Desktop paid | Web; desktop app | Text, images, documents, spreadsheets; folders on desktop | Proprietary |
| WinMerge | Free, open source | Windows | Text, folders, images, CSV and TSV tables | Open source |
| Meld | Free, open source | Linux, Windows | Text, folders | GPLv2 or later |
| Feature | Compare ours | Diffchecker | WinMerge | Meld |
|---|---|---|---|---|
| Texts and code | Yes | Yes | Yes | Yes |
| Word-level highlights | Yes | Partly | Yes | Not stated |
| JSON by key | Yes | Not stated | Not stated | No |
| CSV as a table | Yes | Yes | Yes | No |
| PDFs | Yes | Yes | Not stated | No |
| Pictures | Yes | Yes | Yes | No |
| Folders | No | Partly | Yes | Yes |
| Merge | No | Partly | Yes | Yes |
| Three-way | No | Not stated | Not stated | Yes |
| Export a .patch | Yes | Not stated | Not stated | Not stated |
| No install | Yes | Yes | No | No |
| Mac | Yes | Yes | No | No |
1. Compare (ours)
Best for: Comparing two texts, data files, PDFs or pictures in any browser, and keeping a report or a .patch.
Good
- JSON by key path and CSV by row and cell, not only as text
- PDF text per page, and the pages as pictures with the changes boxed
- Report as HTML or PDF, and a .patch; files read on your device
- Works on your phone, tablet and computer in the browser, even offline
Not so good
- Two files at a time: no folders
- No merging: it shows changes, it does not combine them
- No three-way comparison
2. Diffchecker
Best for: A quick text compare on the web, with a desktop app for offline work.
Good
- Its page says the comparison runs in your browser and nothing is published unless you save and share it
- Compares images, documents and spreadsheets too
- A desktop app for offline use, with a 14-day trial
Not so good
- Unified view, character-level precision and merge are Pro features after a trial, per its page
- Saving a comparison needs an account
Diffchecker website · Sources: Diffchecker home page
3. WinMerge
Best for: Windows users who compare and merge files and whole folders.
Good
- Merges as well as compares, with moved lines detected
- Folder comparison with filters
- Image comparison with an overlay, and CSV/TSV shown as tables
Not so good
- Windows only
WinMerge website · Sources: WinMerge home page
4. Meld
Best for: Developers on Linux who want two- and three-way merges with version control.
Good
- Two- and three-way comparison of files and folders
- Works with Git, Mercurial, Bazaar and Subversion
- Open source
Not so good
- Not yet supported on macOS, per its page
- Its page does not mention pictures or PDFs
Meld website · Sources: Meld home page
Which one to choose
Compare is our pick to compare two files of any common kind on any device, and keep a report: it reads JSON and CSV as data, PDFs by page and pictures by pixel, without uploading them. It does not merge or compare folders.
Choose WinMerge on Windows or Meld on Linux to merge changes and compare folders, and Diffchecker if you want its desktop app or Pro features.
Questions
Are my files uploaded?
Not with Compare: both files are read in your browser. Diffchecker's page says its comparison runs in your browser; WinMerge and Meld are programs on your computer.
Can I compare two Word documents?
Compare reads texts, PDFs and pictures: save the documents as PDF or text first. Diffchecker's page lists documents among what it compares.
What is a .patch?
The changes between two texts in the unified diff format that git and the patch program read. Compare writes one for two texts.
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