Compress PDF

Compress PDF files online without losing quality. Reduce large PDF file sizes instantly without signup, watermarks or uploads.

Compress PDF files online for free without losing quality. Reduce large PDFs by up to 80% instantly - no signup, no watermarks, and 100% private. All processing happens directly in your browser, so your files never leave your device.

Upload your PDF to get started — no sign-up required.

How to Compress PDF Files Online Free

  1. Select your PDF file using the upload button or drag & drop
  2. Choose compression level: Low (maximum compression), Balanced (recommended), or High Quality (minimal compression)
  3. Click Compress PDF and wait for processing to complete
  4. Download your compressed PDF immediately - ready for email, sharing, or upload

Why Use PDFCrush?

  • Reduce PDF size by up to 80% while maintaining document quality
  • Three compression presets for different use cases: email, web, and archive
  • 100% secure and private - files processed locally in your browser
  • Completely free with no registration, watermarks, or file size limits
  • Works on mobile and desktop - no app installation required
  • Handles scanned PDFs, image-heavy documents, and text-based files
  • Instant results - most files compress in under 10 seconds

Your Privacy & Security

Your privacy is protected: all PDF compression occurs client-side in your browser. No files are uploaded to or stored on any server. When you close the tab, all data is automatically cleared from memory.

Frequently Asked Questions

Will compressing a PDF make the text blurry or unreadable?

No. Our compression profiles target unneeded structural metadata and downsample oversized background graphics down to web-standard limits 150 DPI while leaving underlying vector text perfectly untouched.

How much file size can I reduce from a PDF?

You can typically reduce file footprints by 30% to 85% on the source content layout. High-resolution graphics compress deeply, while plain text layout structures see minimal changes.

Can you compress a password protected PDF document?

Yes, provided you enter the valid master owner password. The browser engine uses local decryption routines to unlock the stream, apply compression parameters, and save the file.

Will text remain selectable after running the PDF compressor?

Yes. Unlike crude tools that rasterize pages into flat images, our engine optimizes resources natively, keeping all underlying vector text fully searchable and selectable via Ctrl+F.

Is there a maximum starting file size constraint for local browser compression?

There is no rigid software barrier, but since compression calculations occur in local browser memory threads, documents larger than 100MB may encounter performance thresholds on older computers.

What image compression techniques are applied to background graphics?

The compressor optimizes files by stripping unneeded color maps, clearing metadata markers, and applying lossless or high-efficiency compression parameters directly to image elements.

Why didn't my text heavy layout document show a major reduction in file size?

Text matrices and vector elements are already highly efficient data structures. Significant file size reduction occurs on documents containing high-resolution image assets.

Is my proprietary data secure when processing corporate documents?

Completely. Because the optimization tasks run locally inside your browser sandbox, your files never upload to an external server, keeping your workflow compliant with data-handling policies.