PDF Compare
Free Local ProcessingFree online PDF compare tool that compares two PDF files page by page, pixel by pixel. Differences are automatically highlighted in red and a diff image can be downloaded. Files never uploaded, all processing in your browser.
Drag files here, or
Up to 2, max each 100.0 MB
How to Use
- 1 Upload two PDF files (the first is the original, the second is the modified version)
- 2 Click "Compare PDF" button
- 3 Wait for page-by-page comparison to finish
- 4 View the diff summary (page count difference, pixel diff percentage)
- 5 Pages with differences let you download a red-highlighted diff image
FAQ
Q: Are the comparison results accurate?
This tool compares the rendered output of two PDFs pixel by pixel and can detect all visual differences (text, images, layout). However, "same content but different rendering engines" may cause false positives.
Q: How do I read the diff image?
The diff image uses the modified PDF as the base and marks every differing pixel in red, clearly showing where changes are.
Q: Are files uploaded to the server?
No. All rendering and comparison happen in your browser. Files never leave your device.
Q: What if comparing large files is slow?
Comparison requires rendering each page and comparing pixel by pixel. More pages = slower. We recommend removing irrelevant pages with another tool before comparing.
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