Text Diff Checker
Paste two texts to compare. Differences are highlighted.
About this calculator
Compare two texts and see a summary of added and removed lines, with options to ignore case and whitespace. The sample text is already loaded, so you can try it straight away.
Ignoring whitespace is useful for comparing text that was reformatted but not changed.
How to use it
- Paste the Original Text and Modified Text.
- Tick Ignore case or Ignore whitespace if needed.
- Press Compare.
How the comparison works
The tool splits both texts into lines and finds the longest common subsequence, the largest set of lines that appear in the same order in both. Lines only in the original are shown as removed, lines only in the modified text as added, and the rest as unchanged. This is the same idea used by version control systems.
Worked example
Original: line 1 / line 2 / line 3. Modified: line 1 / line 2 changed / line 3 / line 4
| line 1 | unchanged |
| line 2 | removed |
| line 2 changed | added |
| line 3 | unchanged |
| line 4 | added |
Tips and common mistakes
- Compare line by line, so make sure both texts use the same line breaks.
- Ignore whitespace when comparing text that was reformatted.
- For code, use your editor's diff view as well.
- Use short chunks for clearer results.
- Keep the original safe.
Frequently asked questions
How do I compare two texts?
Paste the original in the first box and the changed version in the second, then press Compare.
What do the colours mean?
Green shows added lines and red shows removed lines.
Does it compare words or lines?
Line by line.
Can it ignore case or whitespace?
Some versions have options for both.
Is my text uploaded?
No.
What is it good for?
Checking edits, comparing drafts and code.