Text Diff
FormattingCompare two blocks of text line by line and highlight additions, removals, and unchanged lines
All processing happens locally in your browser — your data never leaves your machine.
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Examples
Single Line Change
Input
Hello, world!
This is a test.
Goodbye!
---
Hello, world!
This is a demo.
Goodbye!Output
0 additions, 0 removals, 1 change (line 2)Added and Removed Lines
Input
apple
banana
cherry
---
apple
blueberry
cherry
dateOutput
1 addition (date), 1 removal (banana), 1 addition (blueberry)Completely Different Texts
Input
line one
line two
---
alpha
betaOutput
2 additions, 2 removals, 0 unchangedFrequently Asked Questions
- How does the Text Diff tool compare text?
- The tool splits both inputs into lines and uses the Longest Common Subsequence (LCS) algorithm to find the optimal alignment. It then walks the LCS table to classify each line as added, removed, or unchanged, producing a unified diff with accurate line numbers.
- Can I compare large documents with this tool?
- Yes. The diff runs entirely in your browser so there is no upload size limit imposed by a server. Very large documents may take a moment to process since the LCS algorithm is O(m*n) in the number of lines, but typical documents diff instantly.
- Is my data safe when using this tool?
- Absolutely. All comparison logic runs locally in your browser using JavaScript. Your text data is never uploaded to any server.