Compare Two PDFs

When a contract, policy or thesis comes back as "version 2", you need to know exactly what changed — not reread it. This tool compares two PDFs and lists every word that was added, removed or replaced, with the page numbers on both sides, plus a highlighted report you can open in any browser. For scans, drawings and layouts, the visual mode overlays the pages and marks each changed pixel. Both files are compared inside your browser.

How to use this tool

1. Choose the original PDF and the changed PDF.
2. Pick Text to see word changes, or Visual to see which areas of each page differ.
3. Optionally limit the pages on each side — useful when pages were inserted or you only care about one section.
4. Read the table of changes, download the highlighted report or the difference images.

Formula

Text mode extracts the words of both PDFs in reading order and finds the shortest set of insertions and deletions that turns one word list into the other (Myers diff). A deletion directly followed by an insertion is reported as one change.

Visual mode renders each pair of pages at the chosen resolution and flags a pixel when any colour channel differs by more than the tolerance. Pixels that became darker are drawn green (added), lighter ones red (removed), other colour changes orange.

Example

Version 1 says "payment within 30 days" on page 4; version 2 says "payment within 45 days" on page 4 and adds the sentence "Late payments carry 2% interest." on page 7. The result shows 2 differences: a Changed row "30 → 45" (pages 4 / 4) and an Added row for the new sentence (page 7), with 6 words added (45 plus the five new words) and 1 removed.