Text Diff Checker
Compare two texts and see differences line by line. Free, runs in your browser, no signup required.
Free Text Diff Checker — Compare Texts Online
Our Text Diff Checker compares two blocks of text side by side and highlights every difference line by line. Paste your original and modified text, click Compare, and instantly see what was added, removed, or left unchanged.
How does the diff algorithm work?
The tool uses the Longest Common Subsequence (LCS) algorithm to compute an accurate line-by-line diff. Added lines appear in green, removed lines in red, and unchanged lines have no highlight. This is the same approach used by Git and other professional diff tools.
Is it really free?
Yes. This tool runs entirely in your browser — your text never leaves your device. No signup, no limits, no server calls. Use it as many times as you want with any amount of text.
Is my data safe?
Absolutely. All comparison happens 100% client-side in your browser. Your text is never sent to any server, making it safe for comparing confidential documents, source code, contracts, or any sensitive content.
What can I use this tool for?
Compare code changes, review document edits, check translation differences, verify copy-paste accuracy, or diff configuration files. Perfect for developers, writers, editors, translators, and anyone who needs to spot differences between two versions of text.