Free Text Difference Checker Tool Online
Compare two text files or code snippets with line-by-line and word-by-word highlighting. Quickly identify additions, deletions, and changes.
IN: Two text blocks · OUT: Highlighted diff · RUNS: 100% in your browser
Hello world Hello there This is line two Unchanged lineUnchanged line New line added
Frequently asked questions
What's the difference between line and word comparison mode?+
Line mode treats each line as a unit, useful for comparing config files or code; word mode breaks text into words, which is better for spotting small edits inside a paragraph of prose.
How is the diff calculated?+
The tool uses a longest common subsequence (LCS) based diff algorithm — the same family of algorithm used by tools like git diff — to find the minimal set of additions and deletions between the two texts.
What do the colors mean?+
Green highlighted text was added in the 'Changed' box; text with a strikethrough and red/orange highlight was removed compared to the 'Original' box. Unchanged text has no highlight.
Can I compare code files?+
Yes, line mode works well for source code, JSON, YAML, or any structured text where line boundaries are meaningful.
Is there a size limit for the text I can compare?+
The tool can handle documents of several thousand lines comfortably in the browser, though very large diffs (tens of thousands of lines) may take a moment to render.
Is my text uploaded anywhere?+
No, the comparison runs entirely in your browser's JavaScript engine. Neither text box is sent to a server.