Diff Checker

Paste two versions of a text — see every added, removed and unchanged line.

FREE TOOL · WORKS OFFLINE · NO SIGN-UP

Added lines are green, removed lines are red, unchanged lines are grey. The diff is computed with a longest-common-subsequence algorithm over whole lines.

🛠️ How to Use This Tool

  1. 1.Paste the original text on the left box and the changed text in the second box.
  2. 2.Click Compare. The result appears below, line by line.
  3. 3.Read the colors: green means added, red means removed, grey means unchanged — with counts at the top.
  4. 4.Works for code too: compare drafts, config files or two versions of a document.
  5. 5.Nothing is uploaded. The comparison runs entirely in your browser.

❓ FAQ

How does the diff work?

The checker splits both texts into lines and computes their longest common subsequence — the lines both versions share in order. Lines outside that shared sequence are marked added (only in the new text) or removed (only in the old text).

What do the colors mean?

Green lines were added in the changed text, red lines were removed from the original, and grey lines are unchanged in both versions. Counts for all three are shown above the result.

Can I compare code or documents with this?

Yes — anything line-based works: code, configs, essays, lists. Whitespace inside a line counts, so a re-indented line shows as one removal plus one addition.

Is my text uploaded anywhere?

No — 100% free, no sign-up. The comparison runs in your browser; your text is never sent to a server.

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