Diff Checker
Paste the original and the changed version to see exactly which lines were added, removed or kept. Toggle case and whitespace sensitivity, and collapse unchanged lines to focus on the changes.
Paste two versions of a text to compare them.
About this tool
The comparison uses the Myers diff algorithm, the same approach behind git diff, so the result is the shortest set of insertions and deletions that turns one text into the other. Lines that appear in both texts are matched even when they have moved a little, which keeps the output readable for reordered paragraphs and edited code.
Ignore whitespace treats lines that differ only in indentation or spacing as equal, which is handy for code formatted by different editors. Ignore case does the same for capitalisation. Line numbers on the left refer to the original text, those on the right to the changed one, so you can find each change in the source.
Frequently asked questions
- Can I compare code?
- Yes. Paste the two versions; indentation and blank lines are preserved. Turn on ignore whitespace if the files were formatted by different tools.
- Why does a changed line appear as one removed and one added?
- The tool compares whole lines. A line with a single edited character is reported as the old line removed and the new line added.
- Is there a size limit?
- Each side can hold up to 3,000 lines. Larger inputs work best in a desktop diff tool.
- Is my text uploaded?
- No. The diff is computed in your browser; nothing is sent to a server.