Compare PDF
Find every difference between two PDF versions: word-by-word text changes side by side, or a visual pixel overlay.
About Compare PDF
This PDF comparison tool shows every difference between two versions of a document. In text mode, removed words are highlighted in red and added words in green, with both versions side by side and scrolling together. A change list lets you jump straight to each edit. The visual overlay mode compares pages pixel by pixel to reveal changed layouts, images, stamps or signatures.
It is useful for checking a revised agreement, a rent deed, a tender document or a report before you sign or approve it. You can compare PDF online free with no sign-up, and both files are processed in your browser, so confidential documents are never uploaded.
How to use Compare PDF
- Drop the original PDF on the left and the revised PDF on the right, or try the sample pair.
- Text comparison shows removed words in red and added words in green; both sides scroll together.
- Click any entry in the change list to jump to it.
- Switch to Visual overlay to spot layout, image or signature changes pixel by pixel.
Frequently asked questions
Are my files uploaded anywhere?
No. The file is opened and processed entirely inside your browser. Nothing is sent to a server, so it is safe for confidential documents.
Why does the text view say a page has no text?
Scanned PDFs are images without a text layer. Use the Visual overlay tab for them, or run OCR first to make them searchable.
How are changes counted?
Words are compared in reading order using a shortest-edit (Myers) diff. Each run of removed and/or added words between unchanged text counts as one change.
What does the overlay highlight?
Both pages are rendered at the same width and every pixel whose colour differs by more than the sensitivity is painted in the highlight colour. Shifted text shows up as a highlighted band, which is a quick way to spot moved content.
How do I compare two PDF files for differences?
Drop the original PDF on the left and the revised one on the right. Text changes are highlighted at once; switch to Visual overlay to see layout or image changes.
Can I compare a scanned PDF?
Yes, with the Visual overlay, which compares the page images. Text comparison needs a text layer, so run OCR first if you need word-level changes.
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