Loading Techie Utils…

Compare PDFs

See which pages of two PDFs differ, and by how much. Free, and runs entirely in your browser — nothing you enter is uploaded, stored or sent to a server.

About Compare PDFs

Compares two PDFs page by page and says which pages differ and by how much: a similarity score for each, the lines added, removed and changed, and a summary across the whole document.

It compares the text, not the pixels. Two documents that say the same thing in a different font, a different layout or a different page size come out identical here — which is usually what you want when checking whether a contract changed, and never what you want when checking whether a design changed. For a visual comparison, render both to images and compare those.

The page-by-page similarity is the most useful column: a document where one page dropped to 60% and the rest are at 100% tells you exactly where to look, which a single overall diff does not.

Where it helps

  • Page-by-page similarity, which points at where to look rather than dumping one long diff.
  • Counts lines added, removed and changed for each page and for the document as a whole.
  • Handles documents of different lengths without cascading the difference.
  • Both files stay in your browser — comparing two drafts of a contract is exactly the case not to upload.
  • Ignores layout, so a reflowed document is not reported as entirely rewritten.

Limits

  • Text only: an image that changed, a colour that changed or a signature that appeared is invisible to it.
  • It compares page 1 to page 1. A document with a page inserted at the front will show everything after it as different.
  • A scan has no text, so two scans compare as identical — and as empty.
  • The comparison is line-based; a paragraph rewrapped onto different lines reads as several changes.
  • Two hundred pages is the ceiling for one comparison.

Frequently asked questions

Can it show me the differences visually?

Not here. This reads text and reports where it differs. For a visual comparison, run both documents through PDF to Images and compare the pictures — the difference between the two approaches is exactly the difference between "what does it say" and "what does it look like".

Why is every page after page 3 different?

Almost certainly because a page was inserted or removed, so page 4 of one file is being compared to page 5 of the other. Align them first — delete the inserted page from the copy — and run it again.

Both files show as identical — why do they look different?

Then the difference is not in the text: a font, an image, a colour or the layout. Those are all invisible to a text comparison.

Can I compare more than two?

Two at a time. For a set of versions, compare each against the original in turn.

Related tools

More Images & Files tools