Compare PDFs
Compare two PDFs side by side and highlight visual changes in red.
Your files are ready.
Preview or download the results below. Your originals have not been changed.
How to use Compare PDFs (Step-by-Step Guide)
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Step 1: Select or drag your PDF file.
Choose your file using the button above or drag it directly into the workspace dropzone. Your file is read locally into your browser's private memory sandbox using WebAssembly. No files are uploaded to any external server.
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Step 2: Review your pages and parameters.
Inspect original, revised and difference previews page by page. Adjust pixel tolerance, check all pages, and download a difference PNG or page-summary CSV. Corresponding pages align at the top left at equal scale. Visual comparison is not semantic text comparison. Inserted pages, font rendering and compression can affect results. Up to 40 MB per PDF and 100 pages.
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Step 3: Process and download your result instantly.
Click the action button to process your file in device RAM. Once ready, download the finished PDF immediately. Your original source file remains completely unaltered on your computer or phone.
What this tool does & why client-side security matters
Inspect original, revised and difference previews page by page. Adjust pixel tolerance, check all pages, and download a difference PNG or page-summary CSV. Corresponding pages align at the top left at equal scale. Unlike conventional converter platforms that transmit private files across the internet to staging servers, Pactuno processes your data 100% in local device memory. This eliminates data leakage risks, preserves confidentiality under HIPAA and GDPR standards, and avoids mandatory waiting queues.
Before you begin
Visual comparison is not semantic text comparison. Inserted pages, font rendering and compression can affect results. Up to 40 MB per PDF and 100 pages. Maximum file size is 40 MB. Because processing runs on your local CPU and RAM rather than remote cloud servers, large documents execute without upload delays or privacy risks.
Related Guides & Tutorials
Your files stay with you.
File contents are processed on this device. We do not upload your selected files to a server or save them to a Pactuno account. Closing or clearing the page releases this session’s files. Downloaded results remain wherever you save them.
Read the tools privacy detailsFrequently Asked Questions
Is Compare PDFs completely free to use?
Yes. This tool is 100% free with no hidden subscriptions, paywalls, or daily task restrictions. You can process your documents and images as many times as you need without creating an account or providing credit card details.
Are my documents or images uploaded to a cloud server?
No. All processing happens entirely within your web browser using client-side JavaScript and WebAssembly. Your files never travel across the internet, zero bytes are stored on our servers, and your data remains strictly confidential.
Can I use this tool on mobile devices (iPhone and Android)?
Yes. This tool works in any modern mobile browser including Apple Safari on iOS and Google Chrome on Android. Because operations run locally, processing speed depends on your mobile device hardware.
Will this tool affect the text quality or sharpness of my PDF?
No. The client-side PDF engine manipulates internal document object pointers and page trees without rasterizing vector text or compressing embedded fonts. Remaining pages retain 100% of their original sharpness and selectability.
Can I process files offline without an internet connection?
Yes. Once this page is loaded in your browser cache, the client-side engine can execute offline. You can disconnect your internet connection and continue processing files in complete isolation.