Compare PDFs Side by Side or with Overlay

Compare PDFs side by side, use PDF overlay mode, and review visual differences privately in your browser.

First PDF

Click or drop

Second PDF

Click or drop

Compare PDFs Side by Side and with Overlay

What this tool does

This PDF comparison tool lets you open two PDF files and visually compare them in the browser. Use side-by-side mode when you want to read both versions at once, or use compare PDF overlay mode when the documents share the same layout and you need to spot small visual changes in text, spacing, graphics, stamps, or signatures.

How to use it

Upload the first PDF and the second PDF, then choose a viewing mode. Side-by-side comparison places both pages next to each other with synchronized navigation. Overlay mode stacks the pages and lets you adjust opacity or flicker between versions, which is useful for checking tiny layout differences.

Common use cases

Compare PDFs side by side for contract revisions, design proofs, invoices, statements, manuals, labels, forms, and exported reports. Overlay comparison is especially helpful for print files, scanned forms, drawings, and page layouts where a few pixels of movement or a missing mark can matter.

Privacy and output details

Both PDFs are rendered locally in your browser with no upload. This tool is a visual review workspace, so it does not rewrite your PDF files or automatically produce a merged document. Your source files remain unchanged while you inspect page differences on screen.

Related tools: use Extract Pages to isolate pages before comparing, Merge PDF after review, or Organize PDF when one version has pages in the wrong order.

What is PDF Comparison?

PDF comparison is the process of visually analyzing two PDF documents to identify differences between them. Whether you're reviewing contract revisions, checking design changes, or comparing report versions, this tool helps you spot modifications quickly and accurately.

Why compare PDFs?

  • Version Control: Track changes between document revisions
  • Quality Assurance: Verify updates in reports, manuals, or specifications
  • Legal Review: Compare contract versions to identify modifications
  • Design Validation: Check layout changes in brochures or presentations
  • Academic Work: Compare research papers or thesis drafts
  • Business Documents: Review proposals, invoices, or financial statements

Key Features

  • ✓ Side-by-side comparison
  • ✓ Overlay mode with opacity control
  • ✓ Flicker mode for highlighting differences
  • ✓ Synchronized scrolling
  • ✓ 100% private - no upload to servers

How to Compare PDFs

1

Upload PDFs

Upload your two PDF files. Drag and drop or click to browse. Files are processed locally in your browser for maximum privacy.

2

Choose View Mode

Select between side-by-side view or overlay mode. Adjust opacity for overlay, or enable flicker mode to highlight differences.

3

Analyze Differences

Navigate through pages, compare content visually. Use synchronized scrolling for precise comparison of multi-page documents.

Comparison Modes Explained

Side-by-Side View

Display two PDFs next to each other for direct comparison. Perfect for:

  • Comparing large documents with different layouts
  • Reviewing text changes in contracts or reports
  • When you need to see both documents clearly
  • Toggle sync scrolling for coordinated navigation

Overlay View

Layer one PDF over another with adjustable transparency. Ideal for:

  • Spotting subtle layout changes
  • Comparing design elements or graphics
  • Using flicker mode to highlight differences
  • Adjust opacity from 0% to 100% as needed

Frequently Asked Questions

No, all processing happens locally in your browser. This means:

  • Your PDFs never leave your computer
  • No internet connection required after loading the tool
  • Maximum privacy and security for sensitive documents
  • Faster processing as there's no upload/download delay

The tool can handle most PDF files, but performance depends on your device's memory:

  • Recommended: PDFs under 100MB each
  • Large documents: May experience slower rendering
  • For very large files: Consider splitting with our Split PDF tool first
  • Tip: Use our Compress PDF tool to reduce file size if needed

Currently, this tool cannot open password-protected PDFs. However, you can:

This is a visual comparison tool that helps you see differences by eye. It's excellent for:

  • Text changes: Added, removed, or modified text
  • Layout differences: Moved elements, spacing changes
  • Graphical changes: Modified images, logos, or diagrams
  • Formatting changes: Font, color, or style adjustments

Note: This is not an automated text diff tool. For text-only comparison, consider a dedicated text comparison application.

This tool is designed for comparing two PDFs at a time. For comparing multiple documents:

  • Option 1: Compare documents in pairs (A-B, then B-C, etc.)
  • Option 2: For sequential versions, compare each version with its predecessor
  • Option 3: Extract specific pages using our Extract Pages tool for focused comparison

Related guide

How to compare two PDF versions visually

Learn when side-by-side review, overlay comparison, and page-by-page checking help you spot document changes.

Read the PDF comparison guide

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