Text Compare (Diff Checker)

Paste two versions of a text and see every added and removed line highlighted instantly.

Paste two versions above and press Compare.

🔒 Runs entirely in your browser — nothing you type is uploaded or stored on a server.

The Text Compare tool shows you exactly what changed between two versions of a text. Paste the original on the left, the edited version on the right, and press Compare — every removed line is highlighted in red and every added line in green, with unchanged lines shown in between for context. A summary tells you at a glance how many lines were added, removed and left alone.

Comparing documents by eye is slow and unreliable — a single changed word in a contract, an edited paragraph in an essay, or one modified line in a configuration file is easy to miss. A diff checker does the comparison mechanically, the same way programmers review code changes, so nothing slips past. It's invaluable for reviewing edits from a colleague or client, checking what an editor (or an AI) changed in your draft, and verifying two copies of a document really are identical.

Two options make the comparison smarter: ignore extra whitespace treats lines that differ only in spacing as equal, and ignore case does the same for capitalization. Both texts are compared entirely in your browser — nothing is uploaded, so it's safe for contracts, code and confidential drafts.

How to use

  1. Paste the original text into the left box.
  2. Paste the changed version into the right box.
  3. Toggle “Ignore extra whitespace” or “Ignore case” if those differences don't matter to you.
  4. Press Compare — removed lines show in red, added lines in green.
  5. Read the summary tag to see the total number of added and removed lines.

Examples

Reviewing an edit
Paste your draft and the edited version a colleague sent back — every line they touched is highlighted, so you can accept or question each change.
Checking AI rewrites
Compare your original paragraph with a ChatGPT rewrite to see precisely which sentences were altered.
Verifying two copies
Paste both copies of a document; if the result says “identical”, you know no sneaky changes were made.
Config file changes
Compare yesterday's settings file with today's to spot the one line that broke things.

Frequently asked questions

How does the comparison work?
It uses the same longest-common-subsequence approach as programmers' diff tools: it finds the largest set of lines the two texts share, then marks everything else as added or removed.
Does it compare word by word or line by line?
Line by line. Each line of the original is matched against the changed text, which keeps the output easy to scan. For a word-level check on a short passage, put each sentence on its own line first.
What does “ignore extra whitespace” do?
Lines that differ only in spacing — double spaces, tabs, or leading and trailing blanks — are treated as identical, so formatting noise doesn't drown out real edits.
Is there a size limit?
Each side can hold up to 2,000 lines, which covers most documents. For very long texts, compare them section by section.
Can I compare code with it?
Yes — it's line-based, exactly like a code diff. Developers use it for quick comparisons without opening an editor or committing to git.
Is my text uploaded?
No. Both texts are compared entirely in your browser with JavaScript. Nothing is sent to a server, which makes it safe for private and confidential documents.

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