Compare PDF

This tool runs entirely client-side: neither PDF is uploaded to a server. Both files are opened and rendered with PDF.js, displaying matching page numbers from each document next to each other so you can visually scan for differences as you navigate through the pages.

When you run "Highlight Differences," both currently displayed pages are rendered to identical-sized canvases, and the tool performs a pixel-by-pixel comparison — reading the RGB color values at every pixel position in both images and flagging any pair where the combined color difference exceeds a threshold.

Differing pixels are highlighted directly on an overlay canvas, and a percentage is calculated showing roughly what portion of the page differs, giving you a quick visual and quantitative signal of how much changed between the two versions of that page.

Your files are uploaded over an encrypted (SSL) connection. We don't store, read, or share the contents of your files — they're processed to generate your result and are not retained on our servers afterward.

• Checking what changed between two versions of a contract before signing an updated draft.
• Verifying that a revised report matches the original except for the intended edits.
• Auditing a document for unauthorized changes between two points in time.

• Comparing two PDFs that started from different source formats or fonts — formatting-only differences can be flagged even when the actual content is identical.
• Only skimming the summary of differences instead of reviewing each flagged change on a document where accuracy really matters (like a legal contract).

• For a contract or legal document, review every flagged difference individually rather than trusting an overall "changed" or "unchanged" summary.

We respect your privacy. All files are processed securely and are never sold, shared, or used for anything beyond generating your result.