Diff Checker
Compare two texts side by side with highlighted additions and removals.
About this tool
About
This free diff checker compares two texts side by side in your browser. Paste an original and a modified version to see highlighted additions and removals, switch to a unified view, and copy a patch—without uploading anything.
How it works
The tool runs a line-based diff algorithm on your two texts, then refines changed lines at the word level so you can spot edits quickly. Ignore whitespace when spacing alone does not matter. Side-by-side view aligns both versions; unified view shows removals and additions in one stream. Everything stays on your device.
Steps
- Paste the original text on the left and the modified text on the right (or load the sample).
- Review the live highlighted diff below—green for additions, red for removals.
- Toggle Ignore whitespace if you only care about content, not spacing.
- Switch between Side by side and Unified views as needed.
- Copy the unified patch when you want to share or save the change set.
Frequently asked questions
Is this diff checker free?
Yes. It is free to use with no signup. Compare texts as often as you need.
Is my text uploaded?
No. Comparison runs entirely in your browser. Your content is not sent to Utility Tools servers.
What does Ignore whitespace do?
When enabled, lines that differ only by leading or trailing spaces are treated as the same. Useful for comparing formatted code or prose where indentation changed.
Side by side vs Unified?
Side by side shows original and modified in aligned columns. Unified stacks removals (−) and additions (+) in one list, similar to a patch file.
Can I compare code?
Yes. Monospace editors and line numbers work well for code snippets and config. This tool highlights text differences; it does not add language-specific syntax coloring.
Privacy: Your texts stay in this browser. A draft may be remembered in local storage on this device. Nothing is sent to our servers.