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Reduce the file size of a PDF while preserving quality — images are resampled and streams optimized, then download instantly.

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How to Compress a PDF Online for Free

To compress a PDF, add the file above and Signvoy reduces its size in your browser. The document never leaves your device, and there is no account, no email wall, and no file-size limit behind a paywall.

How it works

Compress your PDF in three steps

  1. 1

    Upload your PDF

    Drag and drop your PDF onto the tool or click to browse. The file loads directly in your browser — never sent to any server.

  2. 2

    Compression runs automatically

    mupdf (a professional PDF processing library compiled to WebAssembly) analyses and compresses the document — removing unused objects and recompressing images and fonts.

  3. 3

    Download the smaller PDF

    The tool shows the original size, compressed size, and percentage saved. Click 'Download compressed PDF' to save the result.

Why use Signvoy

Real compression, real privacy

Powered by mupdf WASM

mupdf is the same engine used in professional PDF applications. It removes unused objects, recompresses fonts and images, achieving real file size reductions.

Instant results with size report

The tool shows you the original size, compressed size, and percentage saved before you download — so you know exactly what you're getting.

Your file never leaves your device

The entire compression runs locally in your browser using WebAssembly. Nothing is uploaded or stored anywhere.

Need to send a document for others to sign?

This free tool covers self-serve, one-step document work. Signvoy's full platform adds everything a business needs: send to multiple signers, enforce a signing order, get a tamper-evident audit trail, automate reminders, and attach a certificate of completion to every finished document.

  • Multi-party signing
  • Tamper-evident audit trail
  • Certificate of completion
  • Reusable signing templates
  • Sequential & parallel routing
  • Automatic reminders
  • REST API & webhooks
  • Conditional field logic
Get started free →See all features

FAQ

Common questions

How much can the tool reduce my PDF size?
Results vary. PDFs that contain many redundant objects, uncompressed streams, or high-resolution embedded images see the largest reductions (30–70%). PDFs already optimised by tools like Acrobat may see little or no reduction.
Does compression affect quality?
The tool uses mupdf's lossless compression passes (object removal and stream compression) by default. It does not downsample images, so visual quality is preserved.
Why did my file get larger after compression?
This can happen if the PDF was already maximally compressed and adding mupdf's compression headers adds a small overhead. The tool will still let you download the result.
Is there a file size limit?
The tool accepts PDFs up to 25 MB. Very large PDFs may take longer to process as the mupdf WASM module works through the document in your browser.

Want to learn more? Read the full guide: How to Compress a PDF Without Losing Quality →

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