Compare PDFs
See what changed
Open two versions of a document side by side and see which words changed, page by page. Both files are read in this browser tab — nothing is uploaded to be diffed.
Questions
- Are my files uploaded anywhere?
- No. Every tool on this site runs entirely inside your browser using JavaScript — your file is never uploaded to a server, because there is no server. You can confirm it by opening your browser’s network tab, or by disconnecting from the internet once the page has loaded: the tool still works.
- Does it compare how the pages look, or what they say?
- What they say. Two producers rendering identical words place them a fraction of a point apart, so a pixel comparison of independently generated PDFs is a wall of differences nobody asked about. A page whose layout, font or spacing moved but whose words did not is reported as unchanged.
- What if pages were added, deleted or reordered?
- Pages are matched to each other before any word is compared, rather than lined up one-for-one, so inserting a page at the front does not report every later page as rewritten. A page that simply moved is reported as moved, not as a deletion plus an unrelated addition.
- Why does it say my document has no text?
- Because it is a scan. A scanned page is a picture, so there are no words to compare and every page would otherwise read as entirely new. You need PDFs with a real text layer — a scan has to be run through OCR first, elsewhere.
- Why was one page reported as replaced wholesale?
- Each page pair gets a fixed time budget for the word-level comparison. Two dense pages with almost nothing in common can exceed it, and rather than freezing the tab the tool reports that page as one whole-page change and flags that it did so.
- Can it ignore capitalisation?
- Yes. With that turned on, “Total” and “total” count as the same word, which keeps a restyled heading out of the results.