Skip to main content

Compare PDF Online Free — PrivaTools

TL;DR: Upload two PDFs and download a side-by-side visual diff with differences highlighted — or get a text-only diff report.

Compare two PDFs online for free — upload two versions of a document and get a visual diff highlighting every text change, addition, and deletion. Essential for contract review.

Compare PDF is one of 179+ free file utilities on PrivaTools. The entire stack is open source under the MIT license, so the privacy guarantees can be audited end-to-end. You can also run all 179 tools on your own infrastructure with one docker compose command.

How to Compare PDF with PrivaTools

  1. Upload two PDFs — The first is the baseline; the second is the revised version.
  2. Choose comparison mode — Text: word-level diff. Visual: side-by-side rendered pages with changes highlighted.
  3. Download or view the diff — PrivaTools returns a report PDF with additions in green and deletions in red, plus a summary of changed pages and word counts.

Frequently Asked Questions

Does this work on scanned PDFs?

Only with OCR. Run OCR PDF on both files first so the text layer is present, then compare.

How accurate is the text diff?

Word-level diff handles reordering, insertion, deletion, and formatting changes. Diffs based on character runs would be noisier.

Can I compare more than two files?

Run Compare twice (A vs B, then B vs C) to chain a multi-revision comparison.

Last reviewed 2026-05-01 by the PrivaTools maintainers. Source code on (MIT-licensed, self-hostable).

Related PDF Tools

See how PrivaTools compares to iLovePDF, Smallpdf, Adobe Acrobat, and other free PDF tools.