How to Compare Two PDF Versions and Spot Every Change

The other side sent back “the same agreement with small edits”. A revised circular replaced last month’s. Reading both versions line by line is slow and easy to get wrong. Comparing them with software shows every changed word, moved line and missing page in seconds. Here is how to do it and how to read the results.
Key takeaways
  • Put the original first and the revised version second, so changes read as “before → after”.
  • Text diff lists changed words; Visual diff highlights changes in layout, stamps and images.
  • Use Next diff to jump between changes instead of scrolling.
  • Check both views for contracts — text changes and visual changes can each hide in the other.
  • Comparison runs in your browser, so contracts stay on your device.
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Load the two versions

Open Compare PDF. Add the original under “First PDF” and the revised version under “Second PDF”. If you mix them up, press Swap. The tool compares page by page and shows a summary: identical, minor and major differences, and missing pages.

Three ways to look at changes

Side-by-side shows both versions next to each other, scrolled together — good for a quick read. Visual diff overlays the pages and highlights pixels that changed, which catches edits in stamps, signatures, tables and images that a text comparison can miss. Text diff lists added and removed words, which is the most precise view for clauses, numbers and dates.

Press Next diff and Prev diff to jump from one change to the next.

Tips for contracts and legal documents

Review both Text diff and Visual diff. A changed amount in a table is obvious in text, but a moved signature line or a replaced annexure page is clearer visually. Pay attention to “missing” pages — an entire page removed or inserted shifts everything after it.

If the documents are scans, text comparison needs text: run both through OCR PDF first.

Privacy

Drafts and agreements are sensitive. Compare PDF runs entirely in your browser, so neither version is uploaded.

When comparing PDFs saves the most time

Rental and employment agreements: landlords and HR teams often send a “final” version that differs from the draft you agreed. A comparison shows whether the rent, notice period or a clause changed.

Revised circulars and notices: exam notifications and office circulars are frequently re-issued with corrections. Comparing the new PDF with the old one tells you exactly which dates, eligibility rules or fees changed.

Quotations and invoices: when a vendor sends a revised quotation, compare it with the previous one to catch changed rates or quietly added line items. Reports and theses: check what a reviewer actually changed before you accept their version.

What a comparison can’t tell you

A comparison shows what is different; it can’t tell you whether a change is acceptable. Read each change in context — a single word such as “not” or “may” can reverse a clause.

Very different layouts make comparisons noisy. If one version was re-typeset, every page may show as changed even though the wording is the same; in that case Text diff is the more useful view. And if a document contains images of text, such as scanned annexures, compare those pages visually or run OCR first.

What to do next

Comparing scans? Add a text layer to both with OCR PDF first.

Happy with the final version? Sign it with Sign PDF.

Remove confidential terms with Redact PDF before sharing a comparison copy.

Put the final agreement and its annexures together with Merge PDF.

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Frequently Asked Questions

Can I compare scanned PDFs?

Visual diff works on scans directly. For word-level text comparison, run both scans through OCR PDF first.

What do minor and major differences mean?

Minor pages have small changes, such as a few words or a date; major pages differ substantially or were replaced.

Can I compare PDFs with different page counts?

Yes. Pages that exist in only one version are reported as missing.

Is my document uploaded?

No. The comparison runs in your browser.

Can I export the differences?

You can review them in the tool; for a record, save both versions and note the page numbers the tool reports.