Compare two versions of a PDF and see at a glance what has changed — differences are highlighted in red. Ideal for revisions of drawings, contracts and calculations. 100% in your browser.
Works best when both PDFs have the same page layout. If the page size differs or content has shifted, we flag it per page.
All tools run entirely in your browser: nothing is sent to the server. A password-protected PDF will not open here; remove the protection first with the Unlock tool.
Revision C arrives with the note “minor change” and no hint where it sits. Load the old PDF as version A and the new one as version B. Both are rendered page by page and then compared pixel by pixel. The page bar shows straight away which sheets are identical, which changed and which exist only in the new version; the next-difference button walks you from one deviation to the next. One thing to watch: if a sheet was inserted halfway, everything after it shifts and lights up as well. In that case compare the parts separately.
A text comparison only looks at words. On a drawing the change often sits in a dimension line, a hatch or a detail that moved, and none of that shows up as text. Here the image itself is compared, so everything you can see counts. The trade-off: content that shifted by a few millimetres turns a whole block red even though nothing changed in substance. Switch to the alternating A/B view; if something jumps back and forth, the difference is real. The sensitivity slider handles the rest: lower it for scan noise, raise it when you are hunting one digit in a table.
The difference report (PDF) button records what you found: a cover page with both file names, the date and the number of changed, added and removed pages, followed by every differing sheet (up to sixty) with the changes marked in red. That is what you attach when you reply to a revision. The two PDFs stay on your own computer meanwhile: the comparison runs in your browser and nothing is uploaded, which matters for a contract or a drawing that is not public. A report with dozens of page images does get heavy; if it will not go by email, send it as a download link.