Compare two texts or documents line by line and highlight every added or removed line, with a similarity score. Free, instant and fully private.
Text Diff Checker is part of ToolsPilot — a free online toolkit for PDFs, images, audio and video. No signup, no watermark and no software to install. Your file is processed entirely in your browser, so it never leaves your device.
How to use Text Diff Checker
Paste the original text on the left and the changed text on the right.
Click Compare — added lines show in green, removed lines in red strike-through.
Check the counts and similarity score at the top of the result.
Frequently asked questions
Is Text Diff Checker free to use?
Yes. Text Diff Checker on ToolsPilot is 100% free with no account, no watermark and no daily limits for everyday use.
Are my files private and secure?
Text Diff Checker runs entirely in your browser, so your file never leaves your device — nothing is uploaded to any server.
Do I need to install any software?
No. Text Diff Checker works online in any modern browser on Windows, macOS, Linux, Android and iOS — there is nothing to download or install.
How does the comparison work?
It uses a line-based longest-common-subsequence diff — the same idea used by git — so moved and edited lines are detected sensibly.
Is my text private?
Completely. Both texts are compared locally in your browser and never leave your device.