Diff Checker
Compare two blocks of text and see a line-by-line diff with additions and deletions highlighted
Original
Changed
Diff
Click Compare to see the differences
About Diff Checker
Compare two blocks of text and see exactly what changed, line by line. Paste the original and the changed version, click Compare, and added lines are highlighted in green while removed lines are highlighted in red — computed with a classic LCS diff algorithm, entirely in your browser.
- Line-by-line diff with additions and deletions highlighted
- Optional whitespace-insensitive comparison
- Runs entirely in your browser — nothing is uploaded
Frequently asked questions
Does it diff word-by-word or line-by-line?
Line-by-line — each line is compared as a whole unit, which is the most common and readable way to review text or code changes.
Is there a size limit?
The diff algorithm is O(n×m) in the number of lines on each side, so extremely large inputs (many thousands of lines each) may be slow — the tool will warn you if an input is too large to diff.