Text Diff Checker
Compare two texts side by side and highlight differences. Find added, removed, and changed lines.
About this calculator
Compare two blocks of text side by side and highlight added, removed and changed lines. It is a free online diff checker with no sign-up.
Editors, developers and students use it to check what changed between two drafts or versions of code.
How to use it
- Paste the Original Text and Modified Text.
- Press Compare.
- Review the highlighted lines.
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.