Compare PDFs
Upload two PDF files and compare them page by page with visual difference highlighting. Each page is rendered and compared pixel by pixel, with changes highlighted in a diff overlay. See pages side by side with clear visual indicators of what changed. Runs entirely in your browser — your files never leave your device.
Original PDF
Drop or click to browse
Modified PDF
Drop or click to browse
How to Compare PDFs
Spot every difference between two PDF versions — no signup required.
Upload the original PDF
Drag and drop or click to select the original (baseline) PDF document.
Upload the modified PDF
Add the second PDF — the version you want to compare against the original.
Compare
Click 'Compare PDFs' to render and analyze every page side by side.
Review differences
Browse the page-by-page comparison. Differences are highlighted in red on the diff overlay.
When to Compare PDFs
PDF comparison is invaluable for reviewing contract revisions, verifying design proofs, checking document conversions, and auditing changes between document versions.
Unlike text-based diff tools, visual comparison catches everything: font changes, repositioned elements, color shifts, added or removed images, and layout differences that text comparison would miss entirely.
Our tool renders both PDFs at high resolution using pdf.js, then performs a pixel-by-pixel comparison. Differences are highlighted in red on a separate overlay, with a percentage score showing how much of each page changed. Everything runs in your browser — nothing is uploaded.
Frequently Asked Questions
Are my files uploaded to any server?
No. Both PDFs are processed entirely in your browser. Nothing is uploaded or stored anywhere — your documents stay on your device.
How does the comparison work?
Each page of both PDFs is rendered to a canvas at the same resolution. The tool then compares pixels between corresponding pages and highlights differences in red on a diff overlay.
What if the PDFs have different page counts?
The tool compares all pages up to the maximum page count. Pages that exist in only one document are shown alongside a blank page, and the diff will highlight the entire content.
What kinds of differences does it detect?
It detects any visual difference: text changes, moved images, color shifts, added or removed content. It's a pixel-level comparison, so even subtle changes are highlighted.
Can I compare password-protected PDFs?
Not directly. You'd need to remove the password first using our Remove Password tool, then compare the unlocked PDFs.
Is there a page or file size limit?
No hard limit. Since rendering happens in your browser, very large files may be slower depending on your device's performance.
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