Compare PDF Online
Compare two PDF files visually, review page-by-page differences, and download a comparison report.
Visual comparison
This tool compares rendered page pixels. It can detect visible changes in text, images, layout, and formatting, but it does not perform a semantic document review or explain the meaning of every change.
Processed in your browser
Both PDFs are rendered and compared locally on your device for supported files.
How to compare two PDF files
Choose both PDFs
Select the original PDF and the modified version you want to compare.
Compare rendered pages
Each PDF page is rendered and compared pixel by pixel using the selected sensitivity.
Review the differences
Inspect the original, modified, and highlighted difference images for each page.
Visual PDF comparison
PDF documents can differ in text, images, spacing, page size, fonts, or layout. This tool compares the rendered appearance of two documents and highlights pixels that changed beyond the chosen sensitivity threshold.
Lower sensitivity values detect smaller color differences, while higher values help ignore minor rendering differences such as anti-aliasing. The comparison percentage is a visual estimate rather than a legal or semantic measure of how much document content changed.
If one PDF has more pages than the other, the missing page is compared against a blank page so the difference is visible in the results.
Frequently asked questions
Does this compare PDF text word by word?
No. This version performs a visual page comparison. Text changes are detected when they change the rendered appearance of the page.
What do the red areas mean?
Red pixels indicate locations where the rendered pages differ beyond the selected sensitivity threshold.
Can I download the comparison?
Yes. After comparison, you can generate a PDF report containing the original page, modified page, and highlighted difference view.
Are the PDFs uploaded?
For this tool, supported PDF files are rendered and compared directly in your browser.