Compress PDF on Mac for Free – Tools and Methods Compared
This page is an overview of all free options to compress PDF files on a Mac, covering the built-in Preview method, a paid-once desktop app, and free online tools. Each option is summarised with a one-line verdict on compression quality, ease of use, and when it is the right choice.
H2-1: Option 1 — Mac Preview (Free, Built-In)
How to use: File → Export as PDF → Quartz Filter → Reduce File Size
Compression quality: Applies 72 DPI to all images. Good for large unoptimised PDFs; may increase file size on already-compressed PDFs.
Best for: First-time compression of a large PDF that has never been optimised.
Verdict: Free and instant, but unreliable. Always check output size vs original before using the compressed version.
H2-2: Option 2 — PDF Squeezer 4 (Best Quality, One-Time Purchase)
Price: $5.99 (Mac App Store, one-time purchase, no subscription)
How it works: Drag one or more PDFs onto the PDF Squeezer window. Select a quality preset (Screen, Low, Medium, High, Maximum). Click Compress.
Key features:
- Selectable DPI: 72 / 96 / 150 / 300 DPI per compression profile
- Preserves ICC colour profiles (important for design files)
- Batch processing: drag multiple PDFs at once, no file count limit
- Offline: no files uploaded to any server
- Custom compression profiles: save settings as named presets
Compression ratio (tested on 10MB scanned document): ~74% at Medium quality
Verdict: The best Mac PDF compression app. The $5.99 one-time cost pays for itself immediately over any subscription tool. Recommended for anyone who compresses PDFs regularly on Mac.
H2-3: Option 3 — Free Online Tools (Cross-Platform, No Install)
Online tools work identically on Mac and Windows. The top free options:
| Tool | File Limit | Sign-Up | Compression Ratio | DPI Control |
|---|---|---|---|---|
| PDF Agile (Offline Desktop) | 100MB | Never | ~72% | Screen/eBook/Printer presets |
| iLovePDF | 15MB | No (2 tasks/day) | ~68% | Recommended / Extreme |
| Smallpdf | 15MB | No (2 tasks/hour) | ~65% | Basic / Strong |
| Sejda | 50MB | Never | ~62% | Screen / eBook / Printer |
Best free online choice for Mac: PDF Agile (Offline Desktop) — 100MB limit, no account needed, 72% compression ratio, and no risk of the Quartz Filter size-increase bug.
H2-4: Quick Comparison
| Method | Cost | Offline | Compression | Best For |
|---|---|---|---|---|
| Preview Quartz Filter | Free | Yes | ~35% | Occasional, unoptimised PDFs |
| PDF Squeezer 4 | $5.99 once | Yes | ~74% | Regular use, quality matters |
| PDF Agile (Offline Desktop) | Free | No | ~72% | Best free result, any file |
| iLovePDF Online | Free (limited) | No | ~68% | Occasional single files |
| Ghostscript (CLI) | Free | Yes | ~85% | Power users, command line |
Bottom line: For free + best results, use PDF Agile (Offline Desktop). For the best all-around Mac experience, PDF Squeezer 4 at $5.99 is worth the one-time cost.
Ready to compress your PDF? It's free — no account required.
Try Free Mac-Compatible PDF Compressor — No InstallFrequently Asked Questions
Yes. Mac Preview includes the Quartz Filter (File → Export as PDF → Reduce File Size) which compresses PDFs to 72 DPI. It is free and requires no additional software, but it can increase file size on already-compressed PDFs. For reliable results, use PDF Agile (Offline Desktop) instead.
PDF Agile (Offline Desktop) is the best fully free option: no account, 100MB file limit, ~72% compression ratio, preserves text searchability. For an offline app, PDF Squeezer 4 ($5.99) is the highest-rated Mac PDF compressor on the App Store.
Online: iLovePDF free tier supports 25 files per batch with no account for the first session. Offline free: Automator workflow (see Mac How-To Guide for setup steps) or Ghostscript command-line (via Homebrew, free, no file limit).