Compress PDF
Reduce PDF file size for email and uploads while keeping it readable.
Compress PDF online, free and private
Oversized PDFs are a daily nuisance — an email bounces because the attachment is over the limit, an upload form rejects a scan, or a shared folder fills up with bloated reports. Compress PDF shrinks a heavy document down to a fraction of its size by re-rendering each page as an optimised image and rebuilding a leaner file, so it travels and stores far more easily.
Everything happens right inside your browser. Your PDF is read into memory, re-rendered locally, and handed straight back to you as a download. Nothing is uploaded to a server, so even sensitive scans, contracts, and financial statements never leave your device.
How to compress pdf in your browser
- 1
Add your PDF
Click ‘Select PDF file’ or drop it onto the page. The document is opened locally in your browser — it is never sent anywhere.
- 2
Choose a compression level
Pick a quality or DPI setting to control the trade-off between file size and sharpness. Lower settings squeeze the file harder; higher settings keep pages crisper at the cost of a larger result.
- 3
Compress the file
Press ‘Compress PDF’. Each page is re-rendered to an optimised JPEG image and reassembled into a new, smaller PDF — all on your device.
- 4
Download the smaller PDF
When it finishes, the new file is ready to download in seconds. Compare the before-and-after size, and if it is not small enough, try again with a lower quality setting.
Why use PDFToolz for this
Your files stay private
Compression runs entirely in client-side JavaScript. Because your document is never transmitted, there is no server copy to cache, leak, or subpoena — a genuine benefit for confidential paperwork.
Aggressive, real size reduction
Rather than lightly optimising, we re-render every page as a compressed image and rebuild the PDF from scratch. That approach reliably shrinks image-heavy scans and long reports far more than simple clean-up tools can.
You control the trade-off
The quality and DPI settings put you in charge. Dial the quality down for the smallest possible file to email, or keep it higher when the pages need to stay sharp for reading or printing.
Free, unlimited, and offline
There is no account, watermark, or file cap, and no size limit beyond your device’s memory. Once the page has loaded you can even compress files with the internet disconnected.