How to use the Text Compare (Diff Checker)
- Paste the original text on the left and the changed text on the right.
- Choose whether to ignore spaces or case.
- Click “Compare” and review the highlighted lines.
About this tool
The checker compares the texts line by line using the longest common subsequence method — the same idea behind tools like git diff. Lines that exist only in the new text are marked + (added) and lines that exist only in the original are marked − (removed). A changed line shows as one removal followed by one addition.
It’s handy for checking what a colleague changed in an agreement, comparing two versions of code or a price list, or proofreading an edited essay. Because it runs on your device, confidential documents are never uploaded.
Frequently asked questions
How does the diff checker decide what changed?
It finds the longest set of lines both texts share in the same order; everything else is shown as added or removed.
Can it compare Word or PDF files?
Copy the text out of the document and paste it here. Formatting such as bold or colours isn’t compared — only the words.
Is there a limit?
Up to 5,000 lines per side, which covers most documents. Very large files are better compared with desktop tools.
Is my text kept private?
Yes. The comparison happens in your browser and nothing is sent anywhere.