Text Diff Checker
Paste two versions of any text to see exactly what changed — added, removed, and unchanged lines, highlighted line by line.
See exactly what changed
When you're comparing two versions of something — a contract clause, a config file, a paragraph of copy, a chunk of code — spotting the differences by eye is slow and unreliable. This diff checker does it instantly. Paste the original on the left and the revised version on the right, and it highlights every line that was added, removed, or left untouched, with a running tally of each.
It uses a longest-common-subsequence algorithm, the same approach behind version-control diffs, so it correctly handles insertions and deletions rather than naively comparing line-by-line position. That means adding a line at the top won't wrongly flag everything below it as changed.
Private and instant
Both texts stay in your browser — nothing is uploaded, so it's safe for sensitive documents.
Frequently Asked Questions
How does the text diff checker work?
It compares two blocks of text line by line using a longest-common-subsequence algorithm, then highlights lines that were added, removed, or unchanged between the original and the revised version.
What do the colors mean?
Green lines were added in the second text, red lines were removed from the first, and unchanged lines appear in plain grey. A summary shows the totals.
Is this a line diff or a word diff?
It compares whole lines, which is ideal for code, lists, and paragraphs. Rewording within a line shows as one removed line plus one added line.
Is my text private?
Yes. The comparison runs entirely in your browser — nothing is uploaded or stored.
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