Compare PDF Online

Spot the differences between two PDFs

When a document goes through revisions it can be hard to see exactly what changed between the old and new version. A single word, a moved paragraph, an updated figure or a tweaked price is easy to miss by eye. This compare PDF tool renders the same page from two PDFs and shows them side by side, plus a difference overlay that highlights every pixel that changed. It runs entirely in your browser using pdfjs-dist, so two confidential drafts can be compared without uploading either file to a server.

Load an original PDF on the left and a revised PDF on the right. The tool draws each page to a canvas, and the difference view compares the two images point by point, painting the changed regions in a bright colour over a dimmed copy of the page. That makes edits jump out immediately, even subtle ones that are otherwise easy to overlook in a long contract or report.

Side-by-side and difference views

The side-by-side view is best for reading both versions in context, while the difference overlay is best for pinpointing precise edits. Use the page navigation to move through the documents one page at a time; comparison covers up to the last page that both files share. Because the comparison is visual, it catches changes in text, layout, fonts, spacing, images and stamps — anything that alters how the page looks — which is often more useful than a raw text diff.

Practical uses

Visual PDF comparison helps with contract redlines, proofreading print files, checking that an exported report matches an approved draft, verifying that a regenerated invoice is identical to the original, and reviewing design or layout changes. For the cleanest results, compare PDFs that use the same page size and orientation. After reviewing the highlights, open both originals to read the full context of each change before you approve or reject the new version.