Text Diff Checker
Compare two blocks of text line by line and see exactly what was added, removed, or unchanged, with a summary count.
Compares line by line, entirely in your browser — nothing you paste here is sent to a server. Very large inputs (over 2,000 lines each) aren't compared, to avoid the browser tab becoming unresponsive.
Paste the original text on the left and the changed version on the right, then Compare. Lines that exist only in the original are marked removed, lines that exist only in the new version are marked added, and identical lines are shown unchanged — the same approach source-control diff tools use.
This compares whole lines, not individual words within a line — moving a single word within an otherwise-identical line will show that whole line as removed and re-added, which is expected behavior for a line-level diff, not a bug.
How to use the Text Diff Checker
- Paste the earlier version into Original text.
- Paste the newer version into Changed text.
- Click Compare.
- Read the summary line (+added, −removed, unchanged), then scan the listing: lines starting with + are added, lines starting with − are removed.
- Click Clear to empty both boxes and the result.
Example: Comparing two short lists
Original text apples, bananas, cherries (one per line) against Changed text apples, blueberries, cherries, dates gives +2 added, −1 removed, 2 unchanged. The listing shows apples unchanged, − bananas, + blueberries, cherries unchanged, then + dates.
Questions about the Text Diff Checker
- Why is a line marked as changed when it looks identical?
- Lines are compared character for character, including spaces and letter case. A trailing space, a tab instead of spaces, or a different capital letter is enough for the line to show as removed and re-added.
- Why do I see an extra removed or added blank line at the end?
- If one text ends with a line break and the other does not, the one with the break has an extra empty last line, and the tool reports it as a separate blank line. Windows (CRLF), old Mac (CR) and Unix (LF) line endings are all treated the same.
- How large can the texts be?
- Each side can have up to 2,000 lines. Above that you get the message: Each input is limited to 2,000 lines for this comparison — try a smaller excerpt.
- Is the pasted text sent to a server?
- No. The comparison runs in your browser using a longest-common-subsequence algorithm with no network requests.