Text Diff is a free online tool that compares two texts side by side, highlighting added, removed, and changed lines — and the exact words that changed inside them — with nothing to install and nothing leaving your browser.

Compare two texts

Original

Revised

Ignore whitespace

0 lines added · 0 removed · 0 changed · 0 words changed · 0 unchanged

Enter text on both sides and press Compare — or load the sample.

Result

Added Removed Changed (words highlighted) Unchanged rows are uncoloured.

How it works

Lines are aligned with a longest-common-subsequence (LCS) diff, so a line inserted in the middle of a document shows up as one added row instead of shifting every line after it into false changes. Paired changed lines are then diffed again at the word level (also LCS), so only the edited words are coloured. Ignore whitespace compares lines after trimming and collapsing whitespace runs, while the displayed text keeps its original spacing. Everything runs locally in your browser — your text is never sent anywhere.