Compare two PDFs online to find the differences
Received a new version of a contract and want to know what changed? Certyneo Reader compares the text of both PDFs page by page, shows added lines in green and removed lines in red, and tells you how many pages changed. Everything happens in your browser: neither file ever leaves your device.
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The same PDF reader, installed on your computer: it opens your files offline, with no account, and can become your default PDF reader.
Does Windows show “Windows protected your PC”? That is the usual warning for a newly released app: click “More info”, check that the publisher is Certyneo, then click “Run anyway”.
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Windows (offline installer, x64) · Windows (offline installer, ARM64) · Windows (MSI for managed fleets)
Drop your PDF here
or choose a file on your computer, tablet or phone
Word, Excel, PowerPoint, text, RTF, images and HEIC photos are converted to PDF on your device.
100% local reading: the document is never sent over the internet.
How to find the differences between two PDFs
- 1
Open the first version
Drag the original PDF into the reader or pick it from your device, then open the Compare tool.
- 2
Add the second version
Choose the other PDF: both texts are read and compared page by page, on your device.
- 3
Go through the differences
A summary shows how many pages changed; on each one, added lines appear in green and removed lines in red.
Everything happens in your browser: the file never leaves your device. Open in the reader
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Comparing PDFs: frequently asked questions
What exactly is compared?
The text, page by page. Layout, images, colours and fonts are not compared: a replaced logo or changed formatting will not be flagged.
What if a page was added?
The comparison runs page against page: a page inserted in the middle shifts all the following ones, which then show up as changed. In that case, focus on the first page flagged.
Can I compare a scanned PDF?
Not directly: a scan contains no text. Run each version through the OCR tool first to make it searchable, then compare them.
What if one of the PDFs is password-protected?
A protected PDF must be unlocked first: open it with its password and remove the protection with the Protect tool, then run the comparison.
Are my documents sent to a server?
No. Both PDFs are read and compared in your browser. Certyneo receives neither version, so you can compare a confidential contract without handing it to anyone.
Does this PDF need to be signed?
Send it for electronic signature in minutes: your signers sign from their phone, without creating an account.
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