The most effective way to review PDF changes is automatic visual highlighting — every modified pixel appears in red. Here is how to get instant highlighted differences.
Go to pdfeditor.onl/compare-pdf. Upload your original as File A and the revised version as File B. Files are processed entirely in your browser — no server upload.
Click Compare. The tool renders every page from both documents and performs pixel-level analysis. Changed pixels are highlighted in red on a greyscale background.
Switch to Diff view for the clearest highlights — all changed pixels appear in bright red against a greyscale background.
Tip: Changed pages are marked with an amber badge in the page strip. Click any badge to jump directly to that page.
Click Download All Pages as PDF to export a complete diff report showing all highlighted differences. Ideal for sharing with review teams.
Every pixel that differs between the two PDFs is shown in red — text changes, font changes, layout shifts, added or removed content, and image differences.
Yes. The pixel-based approach works on both digital and scanned PDFs without needing a text layer.
Yes — 100% free at pdfeditor.onl/compare-pdf.