How to shrink a PDF's file size on Mac
You don't need special software to shrink a PDF's file size on Mac. FernPDF runs entirely in Safari or Chrome on macOS: open the tool, drop your file, download the result. Compression re-encodes the document on your device. Image-heavy and scanned PDFs shrink the most, often 60–90%.
On Mac, you drag it straight into the drop zone from Finder, or click to open Safari's or Chrome's native file picker. Once the smaller file is ready, it downloads to your Downloads folder in Finder, the same place Safari and Chrome always save to, Command-Option-L (Safari) or the downloads tray (Chrome) gets you there fast.
Gatekeeper never gets involved, because nothing is installed: no unidentified-developer warning to click through, no .dmg to mount, no permission prompt to grant.
There's nothing to install: no Preview workarounds, no App Store downloads, no Rosetta questions. If your Mac runs a modern browser, it runs FernPDF, on Apple Silicon or Intel.
Step by step
- 1Open the Compress PDF Online Free: Reduce PDF File Size tool in Safari or Chrome on macOS. No install, no account.
- 2Add your PDF: drag it straight into the drop zone from Finder, or click to open Safari's or Chrome's native file picker.
- 3Pick a level: Less, Recommended, or Strong, and preview the estimated savings.
- 4Click “Compress PDF” and download the smaller file. It lands in your Downloads folder in Finder, the same place Safari and Chrome always save to, Command-Option-L (Safari) or the downloads tray (Chrome) gets you there fast.
Common questions
Every FernPDF tool processes files in your browser: read how the privacy model works, or verify it yourself in your network tab.