How to Compress PDF On Mac
Large PDFs are a constant friction point on macOS — they clog email attachments, slow down Finder previews, and eat into your iCloud storage. macOS Preview has a built-in 'Reduce File Size' Quartz filter, but it aggressively downgrades image quality with no control over compression levels. SublimePDF gives you adjustable compression that lets you choose between maximum quality retention and smallest file size.
Follow the step-by-step instructions below, then use the free tool directly — no registration or download required.
Open Tool →How to Compress PDF On Mac — Step by Step
Open the compress tool
Navigate to SublimePDF's compress page in Safari or any Mac browser. You can also drag and drop a PDF directly from Finder onto the upload area.
Upload your PDF
Click to browse or drag your file from Finder, the Desktop, or a Mail attachment directly into the tool. Files up to 100 MB are supported.
Choose compression level
Select from Low (minimal reduction, maximum quality), Medium (balanced — ideal for most documents), or High (maximum reduction for email-friendly sizes). A preview shows the estimated output size.
Compare quality
Use the before-and-after preview to check that images and text remain sharp at your chosen compression level. Zoom into image-heavy pages to verify.
Download the compressed PDF
Click download to save the smaller file. It appears in your Downloads folder and is ready to attach to emails, upload to portals, or store in iCloud.
Pro Tips
- 💡 macOS Preview's 'Reduce File Size' filter under Export often over-compresses images. Use SublimePDF's Medium setting for a balanced result that Preview can't match.
- 💡 If you're compressing a PDF for email, aim for under 10 MB — most email providers reject attachments above 25 MB, and many corporate mail servers cap at 10 MB.
- 💡 Use Quick Look (press Space in Finder) to check the compressed file's quality instantly without opening Preview.
- 💡 For batch compression of multiple files, open several browser tabs and compress files in parallel — each tab processes independently.
Privacy & Security
All processing happens directly in your browser. Your files are never uploaded to any server — they remain on your device throughout the entire process. SublimePDF uses WebAssembly technology for fast, secure, client-side processing.
Works Everywhere
This tool works on any modern browser — Chrome, Firefox, Safari, or Edge — on desktop, tablet, or mobile. No software to install. PDF is an open ISO standard supported by all major platforms.
How to Compress PDF On Mac — FAQ
How does SublimePDF compare to macOS Preview's compression?
Does compression affect the text quality in my PDF?
Can I compress password-protected PDFs?
Will compressed PDFs still be printable at high quality?
Related Guides
How to Compress PDF for Email
Email services typically limit attachments to 25MB. If your PDF is too large, SublimePDF can compress it dramatically while maintaining readable quality — perfect for sending via Gmail, Outlook, or any email service.
How to Compress Images In PDF
Image-heavy PDFs from design files, photo reports, and scanned documents can balloon to hundreds of megabytes, making them impossible to email or slow to load online. Compressing the embedded images is the most effective way to shrink these files because images account for 90%+ of the file size. SublimePDF recompresses every image in your PDF to your chosen quality level while keeping text and vectors untouched.
How to Compress PDF On iPhone
Oversized PDFs on your iPhone make it impossible to share files via iMessage, email, or AirDrop when you're away from your computer. iOS has no built-in PDF compression tool, so files from scanned documents, presentations, or image-heavy reports stay at their original bloated size. SublimePDF compresses PDFs directly in Safari on your iPhone so you can shrink files instantly and share them without delay.