Compare PDF
Compare two PDF documents and find differences
PDF files
Comparison
Similarity, changed lines and page counts show here.
- Similarity
- 0
- Lines added
- 0
- Lines removed
- 0
- Pages (original)
- 0
- Pages (modified)
- 0
Differences
No page
No page
Page images are not available for these files.
No text differences found.
About Compare PDF Documents
Our free Compare PDF tool lets you upload two PDF documents and identify the differences between them. With both visual side-by-side page comparison and line-by-line text diff views, you can quickly spot additions, deletions, and modifications across your documents without any manual effort.
PDF comparison is critical for professionals who need to track changes between document versions, verify contract modifications, or ensure quality control. Our tool calculates a similarity percentage, highlights added lines in green and removed lines in red, and provides detailed statistics including the number of lines added, removed, and page counts for both documents.
This online PDF diff checker processes files securely and generates a downloadable comparison report in PDF format. Check what changed between two drafts of a contract, two versions of a thesis chapter, or two releases of a product manual before you sign off.
Key Features
- Side-by-side comparison of the first 5 pages as images
- Line-by-line text diff with color-coded highlighting (green for added, red for removed)
- Similarity percentage calculation to quantify how alike the documents are
- Detailed statistics showing lines added, lines removed, and page counts
- Page navigation through the first 5 pages of both documents
- Toggle to show only changed lines for focused review
- Downloadable PDF comparison report for record keeping
- Handles large documents
- No watermarks added to comparison results
- Supports PDF files up to 50MB in size
How to Use
- Upload the original PDF: Select the first PDF document (the original or baseline version) using the file picker.
- Upload the modified PDF: Select the second PDF document (the modified or updated version) for comparison.
- Start comparison: Click "Compare PDFs" and wait for the analysis to complete with progress tracking.
- Review visual comparison: Use the "Visual comparison" tab to view the first 5 pages side by side and step through them.
- Review text differences: Switch to the "Text Differences" tab to see line-by-line changes with color coding.
- Download report: Click "Download report PDF" to save a comparison report with the summary and the first 30 changes.
Use Cases
- Contract review: Compare original and revised contracts to identify every change made during negotiations.
- Legal document verification: Verify that only approved modifications were made to legal briefs, agreements, and filings.
- Academic paper revisions: Track changes between manuscript drafts to review edits suggested by reviewers or co-authors.
- Quality assurance: Compare generated documents against templates to ensure compliance with formatting standards.
- Version control: Identify what changed between different versions of reports, proposals, or policy documents.
- Compliance auditing: Verify that regulatory documents match approved versions and no unauthorized changes were made.
- Translation verification: Compare translated documents against originals to ensure layout consistency.
- Publishing proofing: Compare proofs against final manuscripts to catch last-minute errors before printing.
Frequently Asked Questions
Can I compare PDFs with different page counts?
Yes, the tool handles PDFs with different numbers of pages. The page view shows the first 5 pages of both documents and marks a page that one of them does not have; the text comparison covers every page.
Does it detect formatting changes?
The visual comparison shows formatting differences on the first 5 pages, while the text diff focuses on text content changes. Together they provide a comprehensive view of all modifications.
What does the similarity percentage mean?
The similarity percentage indicates how much text content the two documents share. A 100% similarity means both documents have the same text, line for line, while lower percentages indicate more differences. Images and formatting do not count.
Tips & Best Practices
- Upload the original first: Always upload the baseline or original document as "Original PDF" so changes are displayed relative to the original version.
- Use "Show only changes" for large documents: Toggle this option in the text diff view to quickly focus on modified sections without scrolling through unchanged content.
- Check both tabs: Use visual comparison for layout and formatting changes, and text diff for content changes to get a complete picture.
- Download the report: Save the comparison report PDF for your records, especially for legal or compliance documentation.
- Compare clean versions: For best results, compare PDFs that were generated from the same source rather than scanned copies, which often have no text to compare.