Text diff
Compare two pieces of text line by line and see exactly what changed.
- Runs in your browser — your text is never sent anywhere
- No sign-up, no quotas, free to use as often as you like
How it works
Spotting the difference between two nearly identical texts by eye is unreliable and slow. A line-by-line comparison shows you immediately which lines were added, removed or left alone.
How to read the output
Lines that match are prefixed with two spaces. A line only in the original is marked with a minus, a line only in the comparison with a plus. The counts underneath summarise the change.
Line-based, not word-based
The comparison works on whole lines, so changing one word marks the whole line as changed. That is the right granularity for configuration files, lists and code, and coarser than you may want for prose.
How it compares
Line by line, using the same minimal-difference method as git diff (Myers' algorithm). It finds the smallest set of lines to remove and add to turn the original into the new text, so adding one line near the top marks just that line, not everything after it. Removed lines are marked with -, added lines with +, and unchanged lines are left plain.
What counts as a change
Lines have to match exactly, so a difference in spacing or capitals counts. A line that was edited appears as one removed line followed by one added line. Texts of up to 40,000 lines in total can be compared.
Text diff — questions
Does it compare word by word?
No, line by line. A single changed word marks the whole line as different.
Is there a size limit?
Only your browser's memory. Very large files are slower but work.
Is my text uploaded?
No. The comparison happens in the page.