Text Diff Checker

How to compare two texts and find differences

Eyeballing two long versions of the same document is how small changes slip through — a tweaked number in a contract, a dropped paragraph in an essay, one wrong line in a config file. A diff checker does the tedious comparison for you, line by line, and shows only what actually changed.

1. Paste the original into the left box and the modified version into the right box. The diff updates as you type.
2. Read the colors: red lines with a minus were removed, green lines with a plus were added, plain lines are unchanged.
3. Look at the highlights inside red/green pairs — they mark the exact changed words, so you don't re-read whole lines.
4. Swap sides if you pasted them backwards; Clear wipes both boxes (and the autosaved draft).

Reading the diff: red, green, and highlighted words

The comparison is line-based: it finds the longest sequence of lines the two texts share, then marks everything else as removed or added. When a line was edited rather than fully replaced, you see a red line directly above its green replacement, with the changed words highlighted in both — the fastest way to see that "2025" became "2026" or "shall" became "may".

Good uses: essays, code, and contracts

Writers use diff checkers to review a revised draft against the original; programmers compare config files or code before and after a change; anyone reviewing a contract pastes the old and new versions to catch every altered clause. The comparison is exact and case-sensitive — even one changed character shows up.