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Text & Writing

Text Diff Checker

Compare two texts side-by-side with color-coded additions, deletions and changes. No data leaves your browser.

diff result
Enter text in both fields to see the diff

What is Text Diff Checker?

A text diff checker compares two versions of text and highlights the differences between them. It works line by line, identifying which lines were added, removed, changed or left unchanged. This is essential for writers reviewing edits, developers comparing code versions, translators checking localized text, and anyone who needs to spot changes between two documents. Our tool uses color-coded highlighting — green for additions, red for deletions and yellow for modifications — making differences instantly visible. The comparison runs entirely in your browser using JavaScript, so your sensitive documents are never uploaded to any server. Unlike command-line diff tools, this visual interface shows both versions side by side with line numbers, making it easy to trace exactly what changed and where.

How to Use Text Diff Checker

  1. 1

    Paste the original text

    Enter your original or baseline text in the left textarea.

  2. 2

    Paste the modified text

    Enter the updated or modified version in the right textarea.

  3. 3

    Review the diff

    The tool instantly highlights differences with colors. Green means added, red means removed and yellow means the line was changed.

  4. 4

    Copy the result

    Click Copy diff to get a unified diff format you can share or save.

Features

  • Line-by-line text comparison
  • Color-coded additions, deletions and changes
  • Side-by-side view with line numbers
  • Summary statistics (added, removed, changed, unchanged)
  • Copy diff output in unified format
  • Works with large documents
  • Pure client-side — your text stays private

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Frequently Asked Questions

How does the diff comparison work?+
The tool splits both texts into lines and compares them position by position. Lines that exist only in the modified text are marked as added, lines only in the original are marked as removed, and lines that differ are marked as changed.
Can I compare code with this tool?+
Yes. The monospace font and line numbers make it suitable for comparing code snippets, configuration files, SQL queries and any structured text.
Is there a size limit?+
There is no hard limit since everything runs in your browser. However very large texts (over 10,000 lines) may cause slight lag during comparison.
Does it detect moved lines?+
The current implementation compares lines by position. If a line moved from position 5 to position 10, it will show as removed at 5 and added at 10. This keeps the tool simple and fast.
Is my text sent to a server?+
No. All comparison logic runs in your browser. Your text never leaves your device.
Can I compare Word documents?+
This tool works with plain text. Copy the text from your Word document and paste it here. Formatting will be lost but the text content will be compared accurately.