Is this a line-level or word-level diff?

This tool performs a word-level diff, which is more readable for prose. Line-level diffs are better suited for code — use a dedicated code diff tool for that.

Does it handle very long documents?

Yes. The diff runs in the browser using an efficient algorithm. Very large documents (50,000+ words) may take a second but won't crash or upload your text anywhere.

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Text Tools

Text Diff Checker

Compare two blocks of text side-by-side and highlight every addition, deletion, and change.

Last updated July 1, 2026

How to use Text Diff Checker

1Paste the original text in the left panel.
2Paste the revised text in the right panel.
3Differences are highlighted automatically — green for additions, red for deletions.

Why use this tool

Word-level diff highlighting makes changes easy to spot at a glance.
No uploads — everything runs locally in the browser.
Handles large documents without page reloads.
Clear colour coding: green additions, red deletions, unchanged text stays white.

Use cases

Reviewing document revisions

Paste two versions of a contract, article, or proposal to instantly see exactly what changed between drafts.

Catching accidental edits

Compare a published version against an edited copy to make sure only intended changes were made before re-publishing.