Compare PDF
Compare PDF versions to see exactly what changed. Choose the original and the revised file to see the words removed and added, page by page, then download a redline report.
- Input
- Two PDFs: the original, then the revised one
- Output
- A PDF redline report, plus an on-screen comparison
- Runs
- In your browser. The file never leaves your device.
- Cost
- Free. No sign-up, no watermark.
How to compare two PDF files
Choose the two PDFs
Select the original first, then the revised version. Both stay on your device.
Read the differences
See how many pages changed and how many words were removed and added. Step from one difference to the next, and read each page as a redline.
Look at the pages side by side
Switch to the pages view to see both versions together, with every pixel that differs marked in red. It catches changes to pictures, colours and layout that leave the words alone.
Download the report
Click Download comparison report to save a PDF of every difference: removed words in red with a line through them, added words in green with a line under them.
A clear view of what changed
Word-by-word redline
Every page that differs shows its removed and added words in place, with the unchanged text around them, so a changed figure or clause is easy to spot.
Side by side, with differences marked
The two versions of a page sit next to each other, with a red overlay wherever they differ, and the share of the page that changed.
A report you can share
Download the differences as a PDF: a summary, the pages that differ and a redline for each, with long unchanged stretches folded away.
Step through the changes
Jump from one differing page to the next, or pick any page from the list to see how it compares.
Nothing is uploaded
Both files are read and compared in your browser, so a contract or a draft never leaves your device.
Frequently asked questions
How do I compare two PDF files?
Choose the original PDF and then the revised one. The comparison appears at once: a summary of the pages that differ, a redline of the words that changed, and the two pages side by side. Click Download comparison report to keep a copy.
Can I compare two versions of a contract or a report?
Yes, that is what it is for. It shows the words that were removed and added on each page, so a changed amount, date or clause stands out. The files are compared in your browser and are never uploaded.
Does it compare scanned PDFs?
The word comparison needs text, and a scan is a picture of text. Run each file through OCR PDF first, or use the pages view, which compares what the pages look like and works on scans too.
What if a page was inserted or removed?
Each page of the original is compared with the page in the same place in the revised file, so an inserted page makes the pages after it look changed. Use Organize PDF or Extract Pages to line the two files up first. Pages that exist in only one file are reported as such.
Does it find changes to images, colours or layout?
The redline compares words only. The pages view marks every pixel that differs, which shows a swapped picture, a changed colour or a moved block. It compares two pages of the same size, and small differences in how the edges of text are drawn are ignored.
Can I ignore differences in capital letters?
Yes. Choose Ignore capitals and “Total” and “total” count as the same word.
Can I get the text of a PDF to compare it another way?
Use PDF to Text to save the selectable text of each file, in page order, as a plain text file.
Is my file uploaded anywhere?
No. Compare PDF runs entirely in your browser: the file is opened and processed on your own device and is never sent to our server. More in the privacy policy.
Is Compare PDF free to use?
Yes. Compare PDF is free, with no account to create and no software to install — open the page in a modern browser and start.