Text Diff Checker
Paste an original and a changed copy to see exactly which lines were added, removed or left alone. Comparison runs in your browser.
About
Compare two versions of a text and see exactly which lines changed. The comparison runs in your browser using a longest-common-subsequence pass, so the output groups changes sensibly instead of marking everything after the first difference as different.
How to use
- Paste the original into the left box and the changed copy into the right.
- Run the comparison.
- Use the whitespace option if reindentation is drowning the real changes.
Frequently asked questions
Why does it compare lines rather than words?
Line comparison is what version control shows and what most people mean by a change. Word-level diffing is more useful inside a single long paragraph.
What does ignoring whitespace do?
It collapses runs of spaces and trims each line before comparing, so a change in indentation does not count as a change in content.
Is there a size limit?
Around fifteen hundred lines per side, because the comparison cost grows with the product of the two lengths. Beyond that the page asks you to trim the input.