QQudo Tools

Compress PDF Online

Reduce PDF file size with multiple compression modes. All processing happens locally in your browser.

Drag & drop PDF here

or click to select file

Only PDF files are supported

About PDF Compression

This tool lets you compress PDF files directly in your browser. Unlike other online compressors, your PDF files never leave your device. Choose from light optimization that preserves text and structure, recommended compression for balanced results, or strong compression for smallest file size.

How to Use

  1. Click the upload area or drag a PDF file into it.
  2. If the PDF is password protected, enter the password when prompted.
  3. Choose a compression mode: Light, Recommended, or Strong.
  4. Optionally adjust advanced settings like resolution, quality and color mode.
  5. Click "Compress PDF" to start the compression.
  6. Compare the original and compressed file sizes, then download.

Privacy and Security

Your PDF files never leave your device. All compression is performed locally in your browser. We do not record any file names, content, passwords or page data.

Frequently Asked Questions

Are PDF files uploaded to a server?▼
No. All processing happens in your browser. Your PDF files never leave your device.
Why can't some PDFs be significantly reduced?▼
PDFs that are already optimized, contain mostly vector graphics or text, or use efficient encoding may not compress much further. Scanned documents and image-heavy PDFs usually see the most reduction.
Which compression mode is best?▼
Light optimization preserves text and structure but may not reduce size much. Recommended compression balances size and quality for most use cases. Strong compression gives the smallest files but converts pages to images.
Will strong compression affect text search?▼
Yes. Strong compression converts pages to images, so searchable and copyable text will be lost. Use Light or Recommended mode if you need to preserve text search.
Why do images become blurry after compression?▼
Lower DPI and JPEG quality reduce file size but also reduce image clarity. Use higher DPI and quality settings for better image quality.
What is the difference between DPI and JPEG quality?▼
DPI determines the resolution of rasterized pages. Higher DPI means more detail but larger files. JPEG quality controls compression level from low to high, affecting both file size and image clarity.
Why is the compressed file larger?▼
Some PDFs are already highly optimized. Re-encoding pages as JPEG images may actually increase file size for text-heavy or vector-based PDFs. In this case, try Light optimization mode.
Does it support password-protected PDFs?▼
Yes. If your PDF is password protected, you will be prompted to enter the password. The password is only used locally in your browser and is never sent or stored.
Will compression invalidate digital signatures?▼
Yes. Modifying a PDF in any way will typically invalidate digital signatures. This applies to all compression modes.
Can I compress PDF on mobile?▼
Yes. The tool works on mobile browsers. For large PDFs, lower resolution is recommended to avoid memory issues.

Your PDF files never leave your device. All compression is performed locally in your browser. We do not record any file names, content, passwords or page data.