There are several ways to reduce PDF file size on Mac — ranging from Preview's built-in tools to browser-based compressors. Here are the best free methods ranked by effectiveness.
Open Safari, go to pdfeditor.onl/compress-pdf, upload your PDF, select Good or Strong compression, download. This typically reduces size by 40–90% — the best results of any free method.
Open PDF in Preview. File → Export. In the Quartz Filter dropdown, select "Reduce File Size". Save. Note: this often over-compresses images, sometimes reducing quality more than necessary.
Tip: The Preview "Reduce File Size" filter is aggressive — it can reduce quality noticeably. The browser-based method gives more control with multiple quality levels.
Open PDF in Chrome on Mac. Press Cmd+P. Adjust quality settings. Save as PDF. Less effective than dedicated compression but useful for quick reductions.
pdfeditor.onl with Strong compression gives the maximum reduction. Preview's Reduce File Size filter is aggressive but gives less control over quality trade-off.
Yes — completely free in Safari or Chrome on any Mac.