ZeroUtil

PDF Compressor

Optimize PDF file size by re-serializing and stripping unused metadata.

📄

Drop a PDF file here or click to upload

Reduces file size by re-serializing and stripping unused data

How to Use the PDF Compressor

Upload a PDF file by dragging it into the dropzone or clicking to browse. The tool will automatically optimize the file and show you the original and compressed sizes along with the percentage saved.

How Compression Works

  • Re-serialization — The PDF is parsed and re-written, stripping unused objects and metadata.
  • Structure optimization — Redundant data structures are cleaned up during the process.
  • Lossless — Page content, images, and text remain unchanged.

Important Notes

This is a lightweight client-side optimization. Savings vary depending on the original file — PDFs with lots of unused objects or metadata see the best results. Already-optimized PDFs may see minimal or no reduction.

Frequently Asked Questions

How much compression can I expect?

Results vary widely. PDFs with unused objects, metadata, or redundant structures may see 5-30% reduction. Already optimized files may see minimal change.

Will compression reduce image quality?

No. This tool performs lossless optimization by re-serializing the PDF structure. Images and content are not re-compressed or modified.

Why did the file size increase slightly?

In rare cases, re-serialization may produce a slightly larger file if the original was already highly optimized. The original PDF structure may be more compact.

Can I compress password-protected PDFs?

No. The PDF must be unlocked first before it can be processed.

Is my PDF uploaded to a server?

No. All processing happens locally in your browser. Your PDF never leaves your device.

Ad

More PDF Tools