Compare PDF · 3 min read

How to Compare Two PDF Documents Side by Side — Free

Need to find what changed between two versions of a contract, report, or document? Comparing PDFs side by side reveals every addition, deletion, and modification — without reading both documents word by word.

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Step 1 — Open the Compare PDF Tool

Go to pdfeditor.onl/compare-pdf. No account or installation required.

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Step 2 — Upload Both PDF Versions

Upload your original PDF on the left and the revised version on the right. Both files are processed locally — they are never uploaded to a server.

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Step 3 — View the Differences

The tool displays both PDFs side by side with differences highlighted. Added content appears in one color, removed content in another. Scroll through both documents simultaneously to review every change.

Tip: Use the Overlay mode to superimpose both PDFs on top of each other — differences appear as colored highlights. This is especially useful for comparing contract redlines.

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Step 4 — Review and Export

Navigate through the highlighted differences page by page. Use the comparison view to verify that all intended changes are present and no unintended modifications were introduced.

Compare PDF Documents — Free →

Frequently Asked Questions

Can I compare PDFs that have different page counts?

Yes. The comparison tool handles PDFs with different numbers of pages — extra pages in either document are flagged as added or removed.

Does the comparison work on scanned PDFs?

Yes. The pixel-level comparison works on both text-based and image-based scanned PDFs. For text-level comparison on scanned docs, run OCR first.

Is the PDF comparison tool free?

Yes — completely free at pdfeditor.onl/compare-pdf with no account or upload to any server.

Can I compare a PDF and a Word document?

Not directly. Convert the Word document to PDF first using pdfeditor.onl/convert-pdf, then compare the two PDF versions.

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