When reviewing contracts, reports, or any versioned document, you need to know exactly what changed between two PDFs. Here's how to compare PDF documents and find every difference — automatically, in your browser.
Go to pdfeditor.onl/compare-pdf. Upload your original document as File A and the updated version as File B. Both load into browser memory — nothing is uploaded to a server.
Click Compare. The tool renders every page from both PDFs and analyses them pixel by pixel. In seconds, you get a summary showing total pages, changed pages, identical pages, and the average change percentage.
Tip: Pages with significant changes are marked with an amber badge in the page strip at the top — click any badge to jump straight to that page.
Side by Side view shows both versions simultaneously — changed areas are highlighted in red. Overlay slider lets you drag to reveal one version behind the other. Diff view shows a standalone greyscale image with all changed pixels highlighted in red.
Download a single diff page as PNG, or click Download All Pages as PDF to generate a complete diff report. The PDF report is ideal for review meetings, audit trails, and sharing with colleagues.
Yes. The comparison is pixel-based, not text-based, so it works perfectly on scanned and image-based PDFs as well as digitally created ones.
The tool compares at the pixel level at high rendering resolution, so even single-character text changes, minor layout shifts, and subtle image differences are detected.
There is no artificial page limit. Very large documents may take longer to process depending on your device speed and available RAM.