Compare corresponding PDF pages
Compare matching page positions and receive a rendered-pixel difference percentage for each page.
Compare PDF Files Online
Compare two PDF versions by measuring rendered-pixel differences between corresponding pages. Use the text report for visual review, not as semantic, legal, or meaning-level analysis.
or drop the file here
Up to 50 MiB per PDFView limits & supported files
- Supported input
- Select two PDFs
- Limits
- Up to 50 MiB per PDF
- Additional limits
- Up to 100 pages
- Processing
- No file upload
- File handling
- Files remain in your browser
Browser processing
No account required
Direct download
Compare two PDF files for visible differences
Use Compare PDF to measure how much corresponding rendered pages differ. The report gives a per-page percentage but does not show, locate, or classify the changed areas.
Find visible changes between versions
Use the report to identify which page positions changed and by how much; the tool does not locate or classify the changed pixels.
Know what visual comparison cannot prove
A visually similar page can still contain different underlying text, metadata, links, or hidden objects. Do not treat a visual match as a legal or semantic guarantee.
See visible differences between two PDF versions
Compare PDF is a rendered-pixel comparison that produces page-by-page percentages. It is not a semantic text diff, legal verification, or cryptographic integrity check.
Useful for
- Check whether a revised PDF changed visibly.
- Inspect layout shifts between document versions.
- Review page-by-page difference percentages in a downloadable text report.
Good to know
- Corresponding pages are rendered and compared pixel by pixel.
- Very small rendering differences can produce a nonzero percentage score; the tool does not create highlights.
- Changed meaning can exist even when the pages look similar.
How to Compare Two PDFs
Choose the two PDF versions, run the rendered-pixel comparison, review the page-by-page percentage report, and inspect important pages manually.
- Choose the first PDF.
- Choose the second PDF.
- Start the comparison.
- Review the page-by-page percentage scores in the downloaded text report.
- Open the source PDFs separately and inspect important changed pages manually.
Related PDF tools
Browser processing questions
What does Compare PDF actually compare?
It renders corresponding pages on a white background and compares their RGB pixels using the selected threshold.
Does Compare PDF detect changed meaning?
No. A rendered-pixel comparison cannot reliably determine whether wording means something different.
Why can two nearly identical PDFs show small differences?
Font rendering, anti-aliasing, layout shifts, image compression, metadata-driven rendering, or different page dimensions can change the rendered pixels.
Can I compare PDFs with different page counts?
Yes. Pages are matched by page number; extra or missing pages are reported as 100% different.
Is the comparison result a legal verification?
No. It is a review aid and should not be presented as legal, forensic, or cryptographic verification.
Are my files uploaded?
No. Both selected PDFs are processed locally in this browser.
Practical PDF guides for complete tasks
Compare PDF guide
How to Compare Two PDF Files for Visible Differences
Compare two PDFs page by page for visible pixel differences and use the report to identify pages that need closer review.
Read guide →
Compare PDF guide
How to read and verify a PDF difference report
Read the TXT report as a map to pages with pixel differences, then inspect those pages in both source PDFs.
Read guide →
Compare PDF guide
Visual PDF comparison versus text comparison
PDFKaka Compare PDF performs rendered RGB pixel comparison and produces a TXT report.
Read guide →
View all PDFKaka Guides →