OnsitePDF
Sign in

Compress a PDF without uploading

Shrink file size while keeping quality sharp.

Files stay on your device

Drop your PDF here, or click to choose

Files are processed on your device — nothing is uploaded.

Choose file

How to compress a PDF

  1. Drop the PDF you want to shrink — or click to choose it.
  2. Click Process. We losslessly rewrite the PDF's structure for a smaller file.
  3. Download the result. You'll see exactly how much smaller it got.

Your file never leaves your device — compression runs entirely in your browser.

Frequently asked questions

Do I have to upload my PDF to compress it?
No. Compression runs entirely in your browser — your file is processed locally and never leaves your device.
Will compressing reduce the quality?
No. This is lossless, structural compression — it rewrites the PDF more efficiently without touching image quality. If a file can't be made smaller, you get the original back unchanged.
Is compressing PDFs free?
Yes. It's completely free, with no account, no sign-up, and no watermarks.
Can I compress a PDF offline?
Compressing itself needs no internet connection — the work happens on your device, and your file is never sent anywhere. A connection is only needed to load this page and to fetch the compression engine from this site, which happens the first time you compress a file.