How does the diff work?

The tool compares your two texts line by line using the Longest Common Subsequence algorithm. Lines added in the modified text are highlighted green; removed lines are highlighted red.

Can I compare code snippets?

Yes. The tool works with any plain text including source code, though it does not apply syntax highlighting.

Is there a size limit?

No hard limit, but very large inputs (hundreds of thousands of lines) may slow down your browser.

Why use a diff checker instead of reading both texts?

Line-by-line color highlighting reveals single-character changes, moved paragraphs, and deletions that are nearly invisible in a manual read — critical when reviewing contracts, edits, or pull requests.

When is this better than Git diff?

For non-code comparisons: blog post revisions, policy documents, email drafts, student essay versions, or when you don't have both versions committed to a repository.

Text Diff Checker

Text Tools· 20 tools

Free online text diff tool. Paste two versions of text and instantly see line-by-line differences highlighted in color. Added lines shown in green, removed lines in red. Ideal for comparing documents, code snippets, or any text changes.

Original Text

Modified Text

Frequently Asked Questions

References

diff — POSIX utility specification — The Open Group

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Frequently Asked Questions

References and sources

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