Drag & drop your PDFs here
or
Works entirely in your browser
Add two PDFs. The first is treated as the original, the second as the revision - you can swap them once the comparison is up.
About Compare PDF
Text is compared block by block rather than line by line, so adding a sentence on page one does not report every page after it as changed.
A page with no text layer is recognised first, so a scan can be compared with the document it was made from.
Content Overlay draws the two pages on top of each other, which catches what a word comparison cannot: a moved logo, a redrawn table rule, a shifted signature block.
Frequently asked questions about Compare PDF
- Is Compare PDF really free?
- Yes. Compare PDF is free to use with no account, no daily task limit and no paid tier holding features back. Your result is never watermarked and never held behind an email address. The only real limit is your own device, since the file has to fit in your browser's memory while it is being worked on.
- Does my file get uploaded?
- Everything runs inside your browser tab. The file is read with the browser File API, processed in a Web Worker on your machine, and handed back to you as a download. It is never sent to a server.
- Can it compare a scan with a digital document?
- Yes. Any page without a text layer is read by the text recogniser first, and the report names those pages so you know which findings rest on recognition rather than on a text layer.
- What does "rewritten" mean in the report?
- Two passages that mean the same thing but share almost no wording. Matching them takes a small language model that runs on your device; without it the pair is reported as one deletion and one addition instead.
What people use next
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Everything above happens on your device. Compare PDF opens your file in this tab, does the work here, and hands it back - nothing is uploaded, and nothing is kept once you leave.