Text Diff & Compare
Paste two versions of any text and instantly see what changed — line-by-line, with green added and red removed.
How it works
This tool runs a Myers diff algorithm on the two text inputs — the same algorithm used by git diff, diff(1), and most code editors. Output shows lines (or words, if Word-level diff is on) that exist only in the original (red, with a − prefix), only in the changed version (green, with a + prefix), or in both (gray, no prefix).
Everything happens in your browser. Your text is never uploaded.
Use cases
- Editing drafts. Paste the previous version and the new version to see exactly what you (or an editor) changed.
- Comparing legal/contract revisions. Catch every word that was changed between versions before signing.
- Code review. When git is overkill or you're working in a non-git context (Google Docs, email, Slack).
- Translation review. Compare a draft translation to its revision and see only what the editor touched.
- Plagiarism detection (manual). Compare two suspect documents to see how much overlaps verbatim.
Line-level vs word-level diff
Line-level (default) shows whole lines as added/removed/unchanged. Best for code, lists, and structured text where each line is a discrete unit.
Word-level highlights only the changed words within each modified line. Best for prose where small edits ("the" → "a") happen inside otherwise-identical lines. Slower on large inputs.
Frequently asked questions
Is there a size limit?
Up to roughly 100,000 lines per side without slowdown on a modern laptop. Beyond that the diff algorithm slows quadratically — split your text into smaller chunks.
Why don't I see any output?
The diff only renders after you click Compare or stop typing. If both inputs are identical or one is empty, the output area says so explicitly.
Does the diff respect whitespace?
Yes — trailing whitespace and indentation differences will show up. To ignore whitespace, run both sides through our Trim Whitespace tool first.
Can I export the diff?
Right-click in the output → Save as. Or copy the colored output and paste into any rich-text editor (Notion, Word) — the colors carry over.