How to Compare Two PDFs Free — Visual Diff Online

When to Compare PDFs

Contract revisions, document versions, proof checking — you need to spot what changed between two PDF files. Reading both manually is error-prone. Visual comparison highlights every pixel difference between the two documents so nothing slips through.

How to Compare Two PDFs

1. Open the PDF Comparer
2. Upload the original PDF and the modified version
3. The tool renders both side by side and highlights differences in red
4. Review the diff overlay page by page with a difference percentage per page

What Gets Detected

The comparison works at the pixel level — any visual change is highlighted. This includes text changes, moved elements, different images, font changes, color changes, and layout shifts. Even subtle formatting differences are caught.