Compare PDF Files
Use this free Compare PDF Files online tool to compare two PDF files side-by-side and highlight changes. It is built for students, teams, and professionals who need a clean result quickly. Upload, process, and download in a few clicks. Up to 50 MB per file.
How to Use Compare PDF Files
Complete your task in four clear steps.
- Step 1: Upload your original PDF and your modified PDF simultaneously.
- Step 2: Our visual editor displays both files side-by-side.
- Step 3: Our backend performs line-by-line text and pixel region analysis.
- Step 4: Download your highlighted comparison PDF report instantly.
Why Choose OptaPDF for Compare PDF Files?
- Parallel, side-by-side visual viewer synced for easy scrolling.
- Keep text change tracking: added, deleted, or modified content.
- 100% free with secure, private temporary file processing.
Security Guarantee
Your upload is protected with TLS/SSL encryption. Files are automatically and permanently deleted from our servers after 30 minutes. We do not read, share, or store your content. OptaPDF works on iOS, Android, Chrome, Safari, Edge, and desktop browsers without an app installation.
Frequently Asked Questions About Compare PDF Files
Direct answers about using this tool securely and effectively.
Upload both the original PDF and the revised PDF together on our Compare PDF tool to run parallel visual and text scanning.
Yes, our backend text diff algorithm highlights added text, deleted text, and layout shifts.
Yes, our interactive frontend includes synchronized scrolling, allowing you to visually review differences side-by-side.
The downloadable comparison report will follow our naming rule: xy_compared.pdf.
Yes, like all our services, Compare PDF is 100% free with no premium limitations or watermarks.
Yes. Files are processed in our secure sandboxed environments and auto-deleted from our servers within 30 minutes.
For scanned PDFs, we recommend running OCR on both documents first so text differences can be highlighted properly.
Yes! While side-by-side view is best on desktop, our responsive layouts adapt for mobile scrolling.
Our engine will align matching pages and highlight pages that have been completely added or deleted.
You can upload files up to 50MB each.