Free Online Text Compare & Diff Checker
Paste the original and changed text to see exactly what was added, removed or edited.
Tip: Ctrl + Enter to compare · Ctrl + K to clear
How it works
- Paste the original text on the left and the changed version on the right.
- Click Compare (or press Ctrl + Enter).
- Review removed lines in red and added lines in green — changed words are highlighted inside each line.
- Copy or download the result as a unified .diff if you need to share it.
Frequently asked questions
How does the diff checker decide what changed?
It uses the Myers difference algorithm — the same approach used by Git — to find the smallest set of line insertions and deletions that turns the original into the new text, then compares words inside changed lines.
Can I ignore spacing or capitalisation changes?
Yes. Tick "Ignore whitespace" to treat lines that differ only in spaces or tabs as equal, and "Ignore case" to ignore upper/lowercase differences.
Is my text stored anywhere?
No. The comparison runs entirely in your browser, so contracts, code and drafts you compare are never sent to our servers.
How large can the texts be?
Tens of thousands of lines are fine when the texts are similar. If two documents are almost completely different (thousands of changes), the tool will tell you instead of freezing your browser.
Find every difference between two texts
Comparing two versions of a document by eye is slow and error-prone. This diff checker lines up the original and the changed text and highlights exactly what was removed, added or edited — down to individual words inside a changed line.
What you can compare
- Contract drafts and policy documents between revisions
- Source code, configuration files and JSON before and after a change
- Essays, articles and translations after editing
- Lists such as email addresses, product SKUs or keywords
Reading the result
Lines starting with − on a red background exist only in the original. Lines starting with + on a green background exist only in the new version. When a line was edited, the changed words are struck through or highlighted so you can spot a single altered number or name.
Unified diff output
Use Copy as unified diff or download a .diff file to share the changes in the plain-text format used by developers and version control tools like Git.