Compressor - Free Online PDF Tool

Reduce PDF file size directly in your browser. Choose from three compression levels — lossless rewrite, medium JPEG rasterization, or aggressive high-compression mode — and get instant download of the optimized file. Built with pdf-lib for client-side processing.

How to Use

1. Click the upload area or drag and drop your PDF file onto it.
2. Select a compression level: Low, Medium, or High from the dropdown menu.
3. Click the Compress PDF button to start the optimization process.
4. View the results table showing original size, compressed size, and reduction percentage.
5. Click the Download Compressed PDF button to save the optimized file.

Key Features

• Three compression levels
• Client-side processing
• Drag-and-drop upload
• Real-time size comparison
• Instant download

Frequently Asked Questions

What is the maximum file size supported?

The tool supports PDF files up to 100 MB in size. Larger files will need to be split into smaller chunks before compression.

Will compression reduce image quality?

Medium and High compression levels rasterize pages as JPEG images, which reduces quality. Low compression performs a lossless rewrite, keeping text selectable and vectors intact.

Is my data uploaded to a server?

No. All compression happens entirely in your browser using pdf-lib. Your PDF files never leave your device.

Does it work on mobile browsers?

Yes, the tool is fully responsive and works on mobile devices and tablets.

Launch Compressor

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Maintained by Huang Bin · Last updated October 3, 2026