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Compress PDF — without uploading it

Shrink your PDF on your own device with Ghostscript WebAssembly. Images are downsampled, text stays selectable — and the file never leaves your browser.

100% private — files never leave your device

How it works

  1. 1

    Drop a PDF and pick a quality preset.

  2. 2

    The compression engine (a one-time ~15 MB download, then cached) rebuilds the file on your device.

  3. 3

    Compare before and after sizes, then download the result.

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Frequently asked questions

Is my PDF uploaded to compress it?

No. Compression runs on your device using Ghostscript compiled to WebAssembly. The engine itself (~15 MB) is downloaded from this site once and cached — your file never goes anywhere.

How does the compression work?

Ghostscript re-encodes and downsamples the images inside your PDF and rebuilds its internal structure. Text stays selectable and vector graphics stay sharp — pages are not turned into pictures.

How much smaller will my PDF get?

Scanned or image-heavy PDFs often shrink by 60-85% on the Maximum preset. Text-only PDFs are usually already efficient, so the savings there can be small — we'll tell you honestly if compression doesn't help.

Which preset should I choose?

Balanced (150 dpi images) is right for most documents. Use Maximum (72 dpi) for email attachments where size matters most, and High quality (300 dpi) when the PDF will be printed.