Compare PDF
View two PDF pages side by side and highlight their visual differences. Comparison runs entirely in your browser.
Upload two versions of a PDF and see their pages compared side by side with visual differences highlighted, pixel by pixel. Because it compares rendered output rather than text, it catches changes text-based diff tools miss - font swaps, moved images, color shifts, or a table that reflowed differently. Useful for reviewing a redlined contract revision or checking a design proof against an approved layout. Comparison runs entirely in your browser via PDF.js.
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Details
- Category
- Documents & PDF
- Formats
- Runs
- In your browser
- Files uploaded
- No
- Cost per run
- Free
- Sign-in
- Not required
- Works offline
- Yes, once loaded
Last updated 2026-08-03
Common questions
What does the comparison detect?
It compares rendered pixels, so text, image, color, layout, and annotation changes are visible.
Why is a whole area highlighted?
Small layout shifts can move many pixels. Increase the threshold to ignore subtle anti-aliasing and color changes.
Do the two PDFs need the same page count?
Comparison works page by page, so pages are matched by position - documents with different page counts compare only the overlapping pages.
Are my PDFs uploaded anywhere?
No - rendering and pixel comparison both happen locally in your browser.