How to compress a PDF and reduce its file size — privately, in your browser

A job portal, a government form, an email attachment — something has a size limit, and your PDF is just over it. The usual rescue is a free 'compress PDF' site. It shrinks the file, but it also uploads your document to do it, and many add a watermark or push you toward a paid plan. For a routine task, that's a poor trade — particularly when the PDF holds personal or official information.

Why uploading just to compress is risky

To reduce file size, an online compressor takes a full copy of your PDF onto its server. For resumes, certificates, statements and ID documents, that copy is exactly the kind of data you'd rather not scatter around the internet. The compression doesn't require it — browsers are perfectly capable of doing the work locally.

Compression that stays on your device

A client-side PDF compressor opens your file on your own device, re-encodes images and strips unnecessary data to cut the size, and gives you the smaller file back — without uploading anything. No watermark, no queue, no account. Because it runs locally, it's instant and works offline once the page has loaded.

How to shrink your PDF in seconds

Open a browser-based PDF compressor, drop in your file, pick a compression level (more compression for email limits, less to keep text crisp), and download. Rupix's free PDF tools include a private, in-browser compressor alongside merge, split and convert utilities — all at pdf.rupix.io, nothing uploaded.

Get under the limit without wrecking quality

If a PDF is mostly scanned images, compression helps the most; if it's mostly text, it's already small, so try medium settings first to keep it readable. Still too big? Split out the pages you actually need. All of it can be done locally, for free, and your document never leaves your phone.