Text Diff Checker
Compare two texts line by line and spot every change.
Both documents stay on your deviceCompare two texts and find the differences
About this text diff checker
Paste the original text on the left and the changed version on the right to get a line-by-line comparison: added lines are highlighted in green with a + marker, removed lines in red with a −, and a summary counts every change. It uses the same Myers algorithm found in Git, so the diff is minimal — only real changes get flagged. Options let you ignore letter case or trailing whitespace when they don’t matter.
It’s handy for reviewing document revisions, comparing configuration files, checking contract edits, or seeing what changed between two versions of code or SQL. The comparison runs entirely in your browser with JavaScript — neither text is uploaded anywhere, so it’s safe for confidential drafts, credentials, and client data.
How to compare two texts in Word and Excel
Word has a real comparison tool built in, and for long documents it's the best option:
- Open either of the two versions in Word.
- Go to Review > Compare > Compare Documents.
- Pick the old file under Original document and the new one under Revised document, then click OK.
- Word opens a separate document with every difference flagged as revision marks — added text underlined, deleted text struck through.
The catch is that it needs two saved files. If what you have is two blocks of text pasted into the same document, an email, or a chat, it can't help — which is exactly why people drop two snippets into a web tool instead.
Excel has no text comparison of its own. The usual trick is a column with =A1=B1, which returns TRUE or FALSE but is not case-sensitive; if case matters, use =EXACT(A1,B1) — EXACT compares two strings and returns TRUE only when they match exactly, uppercase included. Either way you learn whether the cell changed, not what changed inside it.
The comparator above works straight from pasted text, with no files to save: it marks the added and removed lines one by one, and neither text ever leaves your browser.
Reference tables
FAQ
Is my text uploaded anywhere?
No. The comparison runs entirely in your browser with JavaScript — both texts stay on your device. That makes it safe for contracts, unreleased copy, code, and anything confidential.
Why does a changed line show as removed plus added?
The comparison is line-based: when a line’s content changes, the old version disappears and a new one appears, so you see one − line followed by one + line. This matches how Git and most diff tools report changes.
Is there a size limit?
Each side can have up to 20,000 lines, which covers most documents and source files. Past that limit the tool shows a clear message instead of trying anyway. Below it, the comparison keeps the page responsive for typical documents; two very large files with almost nothing in common can still take a few seconds, and the tool warns you before it starts.