Compress PDF Files

What is PDF Compressor?

PDF Compressor is a free online tool that reduces the file size of PDF documents while maintaining acceptable quality. Whether you need to compress files for email delivery, cloud storage, or website uploads, this tool provides flexible compression options tailored to your needs.

Features

• Multiple Compression Methods: Choose between optimized (fast), image-based (maximum compression), or auto (recommended) methods
• Adjustable Quality Settings: Quality slider from 30% to 100% for image-based compression
• Adjustable Scale Settings: Resolution control from 0.5x to 2x for image-based compression
• Real-time Statistics: View original size, compressed size, compression ratio, and bytes saved
• Compression Preview: See detailed statistics before downloading
• Fast Processing: Quick optimization for already-efficient PDFs
• Maximum Compression: Convert to images for up to 80% file size reduction
• No File Size Limits: Handle PDFs up to 50MB without restrictions
• PDF Preview: Preview compressed PDF before downloading
• Privacy Protected: All processing happens locally in your browser
• No Installation: Works directly in your web browser
• No Registration: Completely free to use, no account needed
• Quick Presets: Pre-configured quality and scale buttons for instant selection

How to Use

Step 1: Select PDF File

• Click the upload area or drag and drop your PDF onto it
• Select a single PDF document to compress (maximum 50MB)
• Files are processed locally in your browser for complete privacy

Step 2: Choose Compression Settings

• Select Compression Method:

  • Auto (Recommended): Automatically selects the best method for your PDF
  • Optimized: Fast method that removes unused objects (5-30% compression)
  • Image-based: Maximum compression by converting pages to images (40-80% compression)

• Advanced Settings (for image-based compression):

  • Image Quality: Adjust slider from 30% (smallest file) to 100% (best quality)
    • Use preset buttons for quick selection: Maximum, High, Standard, Medium, Low
  • Render Scale: Adjust from 0.5x (lowest resolution) to 2x (highest resolution)
    • Use preset buttons for quick selection: 2x, 1.5x, 1x (Original), 0.75x, 0.5x

Step 3: Compress PDF

• Click the "Compress PDF" button to start compression
• Watch the progress bar as your PDF is being processed
• View real-time compression statistics

Step 4: Download Result

• Preview your compressed PDF in the embedded viewer
• View compression statistics:
  • Original file size
  • Compressed file size
  • Compression ratio percentage
  • Total bytes saved
  • Compression method used
• Click "Download Compressed PDF" to save to your computer
• Use "Clear All" to compress another PDF

Perfect For

• Email Attachments: Compress PDFs to stay within email size limits
• Cloud Storage: Reduce storage space on Google Drive, Dropbox, OneDrive, etc.
• Website Uploads: Optimize PDFs for faster web delivery
• Document Sharing: Smaller files mean faster transfers
• Archival: Compress old documents for long-term storage
• Social Media: Create smaller files for sharing on platforms
• Batch Processing: Compress multiple files by repeating the process
• Print Optimization: Prepare PDFs for printing with optimized file sizes

Compression Methods Explained

Optimized Method (Fast)

• Speed: Very fast ⚡
• Compression: 5-30% reduction
• Quality: Excellent - original quality preserved
• Best For: Already optimized PDFs, when speed is priority
• How It Works: Removes unreferenced objects from PDF structure

Image-Based Method (Maximum)

• Speed: Medium 🔄
• Compression: 40-80% reduction (depends on quality settings)
• Quality: Good to Excellent (depends on quality slider)
• Best For: Maximum compression, image-heavy PDFs, email delivery
• How It Works: Renders pages to canvas and converts to JPEG

Auto Method (Recommended)

• Speed: Auto-adjusted
• Compression: Optimized first, smart method selection
• Quality: Balanced approach
• Best For: General use, when unsure which method to use
• How It Works: Uses optimized method automatically

Quality Presets Guide

• Maximum (95%): Highest quality - Best for archival and print-ready documents
• High (85%): Very good quality - Best for professional documents
• Standard (70%): Good quality - Best for general use (recommended)
• Medium (60%): Acceptable quality - Best for email and web sharing
• Low (50%): Lower quality - Best for maximum compression

Scale Presets Guide

• 2x: Highest quality resolution - Best for printing and archival
• 1.5x: High quality resolution - Best for professional use
• 1x: Original resolution - Balanced approach (recommended)
• 0.75x: Lower resolution - Best for general sharing
• 0.5x: Lowest quality resolution - Best for maximum compression

Typical Compression Results

Optimized Method:

• Quality: N/A | Scale: N/A | Compression: 5-30% | Typical Use: All PDFs

Image-based Method:

• Quality: 95% | Scale: 1x | Compression: 20-40% | Typical Use: Professional documents
• Quality: 70% | Scale: 1x | Compression: 40-70% | Typical Use: Email/Web sharing
• Quality: 50% | Scale: 0.5x | Compression: 60-80% | Typical Use: Maximum compression

Technical Details

• Maximum File Size: Up to 50MB per PDF file
• Input Format: PDF (any version)
• Output Format: Standard PDF (fully compatible with all readers)
• Processing: Real-time in your browser with progress tracking
• Privacy: No uploads to external servers - all processing is local
• Browser Support: Works on all modern browsers (Chrome, Firefox, Safari, Edge)
• Performance: Fast compression even with large files
• Methods Available: Optimized, Image-based, and Auto-detection

Tips for Best Results

• Start with Auto: Let the tool automatically choose the best method
• Quality vs Size: Lower quality = smaller file, but may affect readability
• Test First: Try different quality settings to find your sweet spot
• Verify Output: Always review the preview before downloading
• Backup Original: Keep your original PDF in case you need it later
• Preset Buttons: Use preset buttons for quick, tested configurations
• Large Files: Be patient with files larger than 40MB
• Multiple Attempts: Try different methods if first attempt isn't satisfactory

Supported Formats

• Input: PDF files (all versions)
• Output: Standard PDF format

Frequently Asked Questions

Q: Will compression reduce quality? A: The Optimized method has minimal quality loss. The Image-based method's quality depends on the quality slider you choose.

Q: Can I compress password-protected PDFs? A: Currently, the tool works best with unprotected PDFs. Remove password protection first if possible.

Q: What's the difference between the methods? A: Optimized is fast and preserves structure. Image-based offers maximum compression but converts pages to images.

Q: Is my PDF secure? A: Yes! All processing happens in your browser. Your PDF is never uploaded to any server.

Q: Can I compress multiple PDFs at once? A: The current version compresses one PDF at a time. Simply repeat the process for additional files.

Q: What if compression doesn't reduce the file size? A: Some PDFs are already optimized. Try the Image-based method with lower quality settings for more compression.

Q: Will text be selectable after compression? A: With Optimized method, yes. With Image-based method, text won't be selectable as it becomes images.

Q: Why is my PDF not compressing much? A: PDFs with mostly text or already-compressed content won't compress as much as image-heavy PDFs.

Browser Compatibility

• Chrome 90+
• Firefox 88+
• Safari 14+
• Edge 90+

Internet Explorer is not supported.

Credits

• pdf-lib - PDF manipulation and optimization
• pdfjs-dist - PDF rendering engine by Mozilla