How to compare two PDFs and see the differences

YYou receive the "final version" of a contract after two rounds of review and want to know exactly what changed since the last time you approved it. Or your team edited a proposal, and you need to spot every alteration without reading 30 pages line by line. Comparing PDFs manually is tedious and error-prone — a diff tool does in seconds what would take 30 minutes by hand.

This guide shows three ways to compare two PDFs: by text (lists what changed), side-by-side (graphical view), and visual (differences highlighted in red). All free, in your browser.

1. Text comparison

Extracts text from both PDFs and identifies word-by-word differences. Delivers a list of additions, removals, and changes as a report (PDF, HTML, or CSV).

Best for: contracts, technical reports, business proposals — any document where the text is what matters.

2. Side-by-side

Shows both PDFs simultaneously in two columns, with differences highlighted. You can zoom, navigate page by page, and see the full visual context.

Best for: quick visual review when you want to see changes within the original layout.

3. Visual (image diff)

Compares the pages as images, highlighting any pixel that changed in red. Catches alterations that text comparison misses — font changes, spacing shifts, repositioned visual elements.

Best for: designed documents, layouts, reports with charts where visual presentation matters.

1. Upload both PDFs

Upload the original version (PDF A) and the new version (PDF B). Order matters — additions appear as "added in version B", removals as "removed from version A".

2. Pick a mode

Select text, side-by-side, or visual. You can run all 3 on the same PDF pair if you want different perspectives.

3. Process and view

Analysis takes 10-30 seconds. Results stay on the page — text mode shows additions in green and removals in red; side-by-side highlights differences in context; visual shows pages with changed areas in red.

4. Export the report

For text mode, you can download a report in PDF, HTML, or CSV listing all changes. Useful for archiving, attaching to an email, or sending to the other party.

• —Lawyer-reviewed contracts — identify every change made
• —Privacy policy or terms of service — check what changed in the last update
• —Business proposals — confirm agreed changes were made
• —Academic documents — diff between thesis or paper versions
• —Educational material — updates to handbooks, manuals, textbooks
• —Financial reports — compare current quarter vs prior

• —Scanned PDFs (image) — text mode struggles; OCR first or use visual mode
• —PDFs with poor OCR — "phantom" differences appear where recognition was wrong
• —Repositioned tables — text comparison can skip rows if a table moved pages
• —Page-break differences — visual mode highlights this, text mode ignores it
• —Very large PDFs (200+ pages) — visual mode gets slow; prefer text mode here

• —OCR + Compare — for diffing scanned PDFs (run OCR first)
• —Compare + Extract text — to process differences in a spreadsheet
• —Compare + Merge — after spotting changes, build a consolidated version
• —Organize + Compare — align pages before comparing (if structure changed)