Text Tools
Text Diff Checker
Compare two texts line by line and see added, removed and unchanged lines highlighted, in unified or side-by-side view.
Runs in your browser Your input never leaves your device.
About this tool
Paste an original and a changed text to see which lines were added, removed or left unchanged. The tool runs a line-level longest-common-subsequence diff in your browser, marks added lines with + and removed lines with -, and counts each. You can ignore whitespace differences, ignore letter case, swap the two texts, and switch between a unified list and a side-by-side view. Nothing is uploaded. The comparison works on whole lines, so a single changed word marks the entire line as removed and re-added; it does not highlight changes inside a line.
How to use it
- Paste the original text in the left box.
- Paste the changed text in the right box.
- Tick Ignore whitespace or Ignore case if those differences should not count.
- Choose Unified or Side by side and read the +/- counts above the result.
Common problems
- Every line shows as changed
- Check line endings and indentation; tick Ignore whitespace to skip spacing differences.
- Small edit marks the whole line
- The diff compares full lines. Split long paragraphs onto separate lines to narrow the change.
- Message says the texts are too large
- Very large inputs are refused to keep the page responsive. Compare smaller sections.