Compress PDF Online Free — No Signup

Compress a PDF in your browser. Shrink the file size so it fits an email attachment cap, an upload form limit, or just takes less space on disk. The whole job runs locally — your PDF never leaves your machine.

How it works

  1. Drop your PDF. Drag your PDF onto the page, or click to pick one from your computer. Files up to 100MB are supported.
  2. We shrink it locally. GhostPDF re-compresses every embedded image inside your browser. Nothing is uploaded — open DevTools and check the Network tab to verify.
  3. Download the smaller PDF. Save the compressed PDF to your machine. The original is untouched.

Frequently asked questions

How much smaller will my PDF get?

It depends on the file. Scan-heavy and image-heavy PDFs typically shrink 40-80%. Text-only PDFs are already efficient and may only drop 5-15%.

Does compression reduce quality?

Images are recompressed at a moderate quality level chosen to be visually indistinguishable on screen. Text and vector graphics are not re-rasterized and stay sharp at any zoom.

Is it really free? Where's the catch?

No catch. No signup, no document caps, no watermark, no paid tier. GhostPDF is supported by a tiny ad on the tool hub and an optional tip jar — never anything on your file.

Is there a file size limit?

100MB. The limit exists because your browser holds the whole PDF in memory while compressing.

Do you upload my PDF to a server?

No. Compression runs entirely in your browser using WebAssembly. We have no upload endpoint for GhostPDF — only static HTML/JS/CSS loads from our CDN.

Does it work on Mac, Windows, and Linux?

Yes. Any modern browser (Chrome, Firefox, Safari, Edge) on any OS. Nothing to install.

Related tools

Every GhostPDF tool runs entirely in your browser. Your file is never uploaded — there is no upload endpoint to send it to.