Free Online PDF Compressor - Reduce File Size in Your Browser
Compress PDF files to reduce their size while maintaining visual quality - all directly in your browser with zero server uploads. Choose from three compression levels to balance file size reduction against document quality. A live preview shows the exact size reduction before you download, so you always know exactly how much space you're saving. Perfect for shrinking large PDF documents before emailing them as attachments, reducing scanned document sizes for cloud storage, compressing eBooks and manuals for faster downloads, minimizing invoice and report PDFs for web uploads, and optimizing portfolio PDFs to meet submission size limits.
How to Use
- Upload your PDF by clicking the upload area or dragging and dropping your file
- Choose compression level - select Low (minimal compression), Medium (balanced), or High (maximum size reduction)
- The tool instantly analyzes your file and shows the original size alongside the estimated compressed size
- Click Compress to apply the optimization
- Download your compressed PDF and compare the file size savings
Compression Levels Explained
- Low Compression: Minimal optimization that preserves maximum document quality. Best for text-heavy PDFs with minimal images where you want virtually no quality loss.
- Medium Compression (Recommended): Balanced approach that significantly reduces file size while retaining good visual quality. Ideal for most everyday PDF compression needs.
- High Compression: Maximum size reduction for scenarios where file size is critical. Suitable for archival storage, email attachments with strict size limits, or documents where slight quality reduction is acceptable.
How PDF Compression Works
The compressor optimizes PDF files by removing redundant object data, streamlining internal document structures, and applying efficient encoding to embedded resources. Unlike image-based compression that may degrade photo quality, PDF compression focuses on structural optimization - removing duplicate fonts, consolidating metadata, and re-encoding internal streams more efficiently. Text and vector elements remain crisp at all compression levels, while embedded images may see slight quality adjustments at higher compression settings.
When to Compress a PDF
- Email attachments - many email servers reject files over 10-25 MB
- Website uploads - faster page loads with smaller file sizes
- Cloud storage - save space on Google Drive, Dropbox, or OneDrive
- Document archiving - store more files in less space
- Form submissions - meet maximum file size requirements on application portals
Privacy Guarantee
All PDF compression happens entirely in your browser. Files are never uploaded to any server - your sensitive documents remain completely private on your device.
Last reviewed: July 2026.