Compare two PDF files
Got a new version of a contract, an offer or a thesis? See exactly what changed — word by word — instead of reading both from start to finish.
- Put the original PDF on the left and the new version on the right (you can drop both at once).
- Press Compare.
- Read the changes in the Text view, or switch to Visual to see the changed areas of each page in red.
Two ways of looking for differences
The Text view uses the same algorithm as programmers' version control (Myers' diff): it lines up both documents line by line and then word by word inside each changed line. It compares the whole document at once, so added or removed pages do not throw it off.
The Visual view draws each page of both PDFs at the same scale and marks in red the areas whose pixels change. It catches what text cannot: a replaced image, a moved signature, a different stamp or a change in layout.
Worth knowing
Scanned PDFs have no text to compare: use the Visual view, or run OCR PDF on both first.
If the layout changes a lot (different line breaks), the Text view shows those lines as changed even when the words are the same; the word highlighting shows what really differs.
Frequently asked questions
How do I compare two PDF files for differences?
Drop the original and the new version here and press Compare. Removed words appear struck through in red and added words underlined in green.
Does it work if pages were added or removed?
Yes. The text of the whole documents is compared, not page against page.
Can it compare scanned documents?
With the Visual view, yes. For a text comparison, run OCR PDF on both files first.
Are my files uploaded?
No. Both PDFs are read and compared inside this browser tab.