Diff Checker
Compare two texts and see exactly which lines were added, removed or left unchanged.
| 1 | 1 | Free online tools | |
| 2 | − | No signup required | |
| 2 | + | No signup, no watermark | |
| 3 | 3 | Works on any device | |
| 4 | + | Files never leave your browser | |
| 4 | 5 | Contact: hello@example.com |
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Spot Every Change Between Two Versions
Reading two versions of a document side by side, it's easy to miss a changed figure or a deleted sentence. A diff lines them up and marks every addition and removal, so you can review edits to a contract, check what a colleague changed in a config file, or confirm two exports really are identical.
How to Compare Two Texts
- Paste the original. Put the older version of the text in the left box.
- Paste the changed version. Put the newer version in the right box.
- Review the differences. Added lines are marked + in green and removed lines − in red, with line numbers from both versions.
- Adjust the options. Ignore case or whitespace, or show changes only, to focus on the differences that matter.
Frequently Asked Questions
How does the diff checker decide what changed?
It uses the Myers diff algorithm, the same approach behind git diff, to find the smallest set of line additions and removals that turns the original text into the changed one.
Can it ignore whitespace or capitalisation?
Yes. Ignore whitespace treats lines as equal when they differ only in spacing or indentation, and Ignore case treats upper and lower case as the same. The original text is still shown.
Is there a size limit?
There is no fixed limit on length. Very large texts that differ in more than 3,000 lines are refused, because a line-by-line view of that many changes isn't useful and would use a lot of memory.
Are my texts uploaded?
No. The comparison runs in your browser. Contracts, code and private documents never leave your device.
Can I compare code?
Yes. It works with any plain text, including source code, JSON, CSV, configuration files and essays.