Text Diff Checker
Paste the original and the changed version. Lines only in the original are red, lines only in the new version are green.
How the comparison works
This tool compares line by line using a longest-common-subsequence algorithm, the same approach behind most "diff" tools — it finds the longest run of lines both texts share and marks everything else as added or removed around that.
About the Text Diff Checker
Text Diff compares two blocks of text line by line and shows which lines were added, removed or left unchanged. Use it to review edits to an article, compare versions of code or configuration, or check what changed in a contract.
The tool aligns the two texts using a longest common subsequence approach, which finds the largest set of lines that appear in both in the same order. Lines only in the original are marked as removed and lines only in the changed text as added. It compares whole lines, so a small edit inside a long line marks the whole line as changed.
How to use it
- Paste the original text on the left.
- Paste the changed text on the right.
- Press Compare.
- Read the colour-coded Result.
Tips and good to know
- Break long paragraphs into lines for finer comparison.
- Trailing spaces count as differences.
- For PDFs use the PDF Compare tool.
Frequently asked questions
Does it compare words?
It compares lines.
Can it ignore case?
No, differences in case show as changes.
Is my text uploaded?
No.