Compare two texts side by side and highlight differences. Toggle between line-level and word-level diff. See counts of added, removed, and unchanged lines with color-coded output.
LevnTools Text Diff lets you analyze and transform text directly in your browser. Everything runs locally in your browser — your text and strings never leave your device. Unlike cloud-only alternatives that require uploads and accounts, this tool is completely free with no usage limits or watermarks. It is designed for writers checking word count and readability, students formatting essays and papers, developers manipulating string data — anyone who needs a fast, reliable text tool without the overhead of installing software. Just open the page and start working.
Text Diff is used by a wide range of people. Explore how different groups use this tool:
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Line-level diff compares texts one full line at a time, marking entire lines as added, removed, or unchanged. Word-level diff splits the text into individual words and highlights exactly which words changed, giving a more granular view.
The tool computes the Longest Common Subsequence (LCS) between the two texts, then marks tokens not in the LCS as additions or deletions. This is the same approach used by Git and most professional diff tools.
Yes. For texts with over 5,000 lines, the diff computation runs in a background Web Worker to keep the interface responsive. There is no strict size limit.
Green background indicates text that was added in the modified version. Red background indicates text that was removed from the original. Lines without color highlighting are unchanged between the two versions.
Completely. Both texts are compared locally in your browser. Nothing is sent to any server. The tool works fully offline once the page has loaded.