Text Diff
This free online text diff tool compares two pieces of text and shows exactly what was added, removed and kept — instantly, as you paste.
How to use
- Paste the original text into the left editor and the changed text into the right editor.
- Pick a comparison level: word by word for prose edits, or line by line for lists, code and configuration.
- Switch between the inline view and the side-by-side view; additions, deletions and unchanged parts are marked automatically.
Frequently asked questions
How is this different from other diff checker websites?
The comparison algorithm is the same classic idea, but this tool runs entirely in your browser: your two texts are never uploaded to any server. You also get both a word-level and a line-level mode plus inline and side-by-side views without paying or signing up.
When should I use word comparison instead of line comparison?
Word comparison is best for prose: it pinpoints the exact words that changed inside a sentence. Line comparison is best for lists, logs, code and configuration files, where a changed line is usually rewritten as a whole.
What does the side-by-side view show?
It places the original on the left and the changed text on the right. Removed lines are highlighted in red on the left, added lines in green on the right, and a rewritten line appears as a red-green pair so you can see the before and after next to each other.
Can I compare code or documents with Chinese text?
Yes. Comparison is Unicode-aware, so Chinese, Japanese and Korean text works the same as English. For code, use line comparison; indentation differences are treated as changes, which is usually what you want to catch.
Are my texts uploaded or stored?
No. The diff is computed locally in your browser the moment you type. Neither text ever leaves your device, nothing is stored or logged, and everything is gone when you close the page.
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About this tool
This free online text diff tool compares two pieces of text and shows exactly what was added, removed and kept — instantly, as you paste. It is built for contract review before you sign, proofreading a revised draft against the original, checking what a colleague actually changed in a paragraph, and verifying that copied configuration or translated copy differs from the source in only the ways you expect. Choose word-level comparison to catch rewording inside a sentence, or line-level comparison for lists, logs, code and configuration files where whole lines move. Two views fit two habits: the inline view marks changes right inside the merged text, while the side-by-side view puts the original and changed versions in facing columns, with every edit paired row by row. Unlike many diff checkers, this one runs entirely in your browser — both texts are compared locally on your own device and never uploaded, so unreleased contracts, private documents and confidential code stay on your machine. Paste both versions below and the comparison updates in real time.