Compare PDF
See the visual differences between two PDF files.
or drag and drop
or drag and drop
Compare PDF shows you the differences between two versions of a PDF document — highlighting what text has been added, removed, or changed between the two files. Document comparison is essential in legal, contract, and editorial workflows where tracking changes between versions is critical: a contract sent for review that comes back with modifications, a policy document updated since the last review, a report revised after feedback, a regulatory filing amended before resubmission. iSavePDF's Compare PDF tool extracts the text from both PDFs using pdfjs-dist and produces a highlighted comparison showing exactly what changed, entirely in your browser. Neither file is ever uploaded to a server. The tool is free with no account required.
Step by step
How to compare pdf on iSavePDF
Open Compare PDF on iSavePDF
Navigate to isavepdf.com/compare-pdf in any modern browser — Chrome, Edge, Firefox, Safari, or Brave on desktop or mobile. No extension, installation, or account is required.
Upload the original and revised PDFs
Upload the original (before) PDF into the first upload zone and the revised (after) PDF into the second. The tool accepts PDFs up to 50 MB each. The comparison is directional — changes are shown as additions or deletions relative to the original.
Run the comparison
Click Compare. pdfjs-dist extracts the text from both PDFs and a diff algorithm identifies additions (text in the revised version that wasn't in the original) and deletions (text in the original that isn't in the revised version). This runs entirely in your browser with no uploads.
Review the differences
The results are displayed as a highlighted diff — added text in green, deleted text in red — so you can see exactly what changed between the two versions. Scroll through the comparison to review all differences, or use the navigation controls to jump to the next or previous change.
Export the comparison report
Download the comparison report as a PDF or plain text document for your records. This is useful for meetings, contract negotiations, or version control documentation where a record of what changed between versions is needed.
How it works
How Compare PDF works
Upload both PDFs
Drop the original and the modified version of your PDF.
Click Compare
Each page is rendered and compared pixel by pixel. Changed areas are highlighted in red.
Download the comparison PDF
Each page shows original, modified, and diff side by side — saved to your device.
When to use it
Common use cases
Reviewing contract redlines
When a contract is sent to counterparties for review and comes back with modifications, the standard workflow is to compare the returned version against the version that was sent. Manual comparison of legal documents is error-prone and slow. Automated comparison identifies every change — including subtle wording modifications, moved clauses, and changed numbers — with none missed. Because contracts contain commercially sensitive and legally privileged content, local comparison with no server upload is the appropriate approach.
Verifying document integrity
Documents that are transmitted electronically — policies sent for signature, reports sent for approval, regulatory submissions — occasionally arrive back with changes that weren't authorised. Running a comparison between the sent version and the returned version immediately highlights any differences, providing a record of what was changed and when. This is particularly important for legal documents, regulatory filings, and financial reports.
Tracking policy and compliance document updates
Internal policies, regulatory compliance documents, and operating procedures are updated periodically. When a new version is issued, the relevant teams need to understand what changed — not just that the document was updated. Running a comparison between the old and new version produces a clear record of the changes that were made, which is often required for compliance training and change management processes.
Proofreading revised documents
After a document goes through review and editing cycles, the author or editor needs to verify that the changes made are exactly what was intended — no unintended deletions, no incorrect text insertions, no introduced typos. Comparing the pre-edit and post-edit versions surfaces any discrepancy between what was intended and what was actually changed, catching errors that might not be noticed in a linear re-read.
Why iSavePDF
The privacy-first way to compare pdf
The documents people compare are almost invariably sensitive: contracts under negotiation, legal filings, policy documents, financial reports, regulatory submissions. Online PDF comparison tools require uploading both versions to a server — which means two documents potentially containing confidential, legally privileged, or commercially sensitive information crossing the network to infrastructure you don't control.
iSavePDF runs the comparison entirely in your browser. Both PDFs are read from your device into browser memory, the text is extracted locally using pdfjs-dist, and the diff is computed in the browser's JavaScript engine. No file content is transmitted anywhere. You can verify this using browser DevTools — open the Network tab and run a comparison to confirm no outbound file transfer occurs. The tool is free and funded by display advertising.
Tips & limits
Tips for the best results
Comparison works on text content only
The comparison identifies differences in the text extracted from both PDFs. Visual differences — changed images, moved graphics, reformatted layouts — are not detected. If you need to identify visual differences between scanned PDFs or image-based pages, you'll need an image comparison tool rather than a text comparison.
Scanned PDFs may produce unreliable results
If either PDF is scanned (contains images of pages rather than embedded text), pdfjs-dist will extract little or no text, and the comparison will be meaningless. Text-based PDFs (native digital documents, PDFs exported from Word or other applications) work correctly.
Structural changes may create false positives
If the two PDFs have different page layouts or structures (for example, a document that was reformatted), the comparison may flag many differences that are layout-related rather than content-related. The comparison operates on extracted text sequences, not on the semantic structure of the document.
Use with other iSavePDF tools for document workflows
If you need to redact the differences before sharing the comparison report, use iSavePDF's Redact PDF tool. If you need to merge the comparison report with supporting documents, use Merge PDF.
FAQ
Frequently asked questions
- Yes — completely free with no account and no usage limits.