MammothPDF
Tools

Compare PDFs

Drop the original and the changed version. The words of every page are compared - removed ones struck through in red, added ones in green - and, in visual mode, the pages are compared pixel by pixel too, so a moved logo or a redrawn chart shows as a boxed area. The changed pages are marked in the preview and the whole comparison is saved as a report PDF. Everything runs in your browser; the files never leave your device.

Drop PDF files here

Drag them straight from your desktop

or
  • PDF files only
  • Up to 15 MB each
  • 2 files a run - unlimited with Pro

Frequently asked questions

What does the tool compare?

The words of each page against the same page of the other file: what was removed is struck through in red, what was added is green, with a few words of context around each change. In visual mode the pages are also compared as pictures, so a moved logo, a redrawn chart or a change in a scan without a text layer shows up as a boxed area. Everything runs in your browser - the two files are never uploaded.

What do I get?

A report PDF: a summary, then every changed page with its removed and added words and, in visual mode, the two pages side by side with the changed areas boxed. On screen the changed pages are marked in the preview and the differences view lists the word changes.

Which file is the original?

The first one in the list. Drag the rows or press "Swap the two" to turn them round - the report says which is which.

Does it work on scans?

Text mode needs a text layer - run a scan through OCR first, or use visual mode, which compares the page images directly. Pages are paired by number; if a page was inserted, everything after it will show as changed.

Missing something, or did the result surprise you?

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