Text Diff Checker
Paste an original version and a changed version of any text, then compare them line by line. Removed lines are highlighted in red, added lines in green — calculated entirely in your browser.
How to Use the Text Diff Checker
- Paste the original version of your text into the left box.
- Paste the updated version into the right box.
- Click "Compare" to run a line-by-line comparison.
- Lines only in the original are shaded red in the left panel; lines only in the changed version are shaded green in the right panel. Lines that appear in both are shown unhighlighted.
Why Use This Tool?
Is my text uploaded anywhere?
No. The entire comparison runs inside your browser using JavaScript — nothing you paste is sent to a server, logged, or stored. This makes it safe to compare contracts, private drafts, or any sensitive text without it ever leaving your device.
How does the comparison work?
The tool splits both inputs into individual lines and matches them against each other to find which lines are shared and which are unique to one side. Lines that exist unchanged in both versions are left plain; anything only in the original is marked as removed, and anything only in the changed version is marked as added — the same core idea used by version control diff tools, applied to plain text or prose.
Can I compare full paragraphs or just short snippets?
Both. The comparison works line by line regardless of length, so it's equally useful for comparing two full-page drafts of an article or two short one-line captions. Because it compares whole lines, moving a sentence to a different line — even with identical wording — can appear as a removal plus an addition, so it's best suited to catching wording changes rather than deep semantic rewrites.
Who uses a text diff checker?
Editors comparing two drafts of an article to see exactly what changed, contract reviewers checking a redlined agreement against the original, and students comparing revision notes all rely on a fast visual diff to spot differences without reading every line manually.