By PDFKits Team — Published July 2, 2026
Mac users regularly deal with large PDF files, whether it's design mockups from creative apps, scanned documents, or lengthy reports. These files can quickly balloon to tens or even hundreds of megabytes, making them difficult to share via email or upload to cloud storage services with file size limits.
Most email providers cap attachments at 20–25 MB, and many corporate email servers impose even stricter limits of 5–10 MB. Cloud storage services like iCloud, Google Drive, and Dropbox work better with smaller files that sync faster and consume less of your quota. Compressing your PDFs before sharing saves bandwidth, storage space, and ensures your recipients can actually receive your files.
Whether you need to email a contract, upload a presentation, or simply free up disk space on your Mac, having a reliable method to compress PDFs is essential. Below are four free methods you can use right now, ranked from easiest to most technical.
The quickest way to compress a PDF on Mac is to use an online tool that works directly in your browser. No software installation, no configuration, and it works on every Mac regardless of your macOS version.
This method is ideal for most Mac users because it requires zero setup. Your PDF never leaves your browser since all processing happens locally, which also means your documents stay private and secure.
Need a specific file size? Try our Compress PDF to 200KB or Compress PDF to 1MB tools for precise control over the output size.
Every Mac comes with Preview, Apple's built-in document and image viewer. Preview includes a basic PDF compression feature that can reduce file sizes without installing any additional software.
While Preview is convenient because it comes pre-installed on every Mac, it has a significant limitation: you have no control over the compression quality. The "Reduce File Size" filter uses aggressive compression that can noticeably degrade image quality in your PDF. For documents with important images, charts, or graphics, you may find the results unacceptable.
Preview works best for text-heavy documents where image quality is not a primary concern. For more control over the balance between file size and quality, an online tool like PDFKits gives you multiple compression levels to choose from.
If you regularly need to compress multiple PDFs, macOS Automator can help you create a reusable workflow that processes files in batch. This method requires a bit more initial setup but pays off if PDF compression is part of your regular workflow.
You can now drag multiple PDF files onto your Automator workflow to compress them all at once. This is particularly useful for photographers, designers, or anyone who handles large batches of PDF documents regularly.
Note that Automator uses the same Quartz Filter as Preview, so the compression quality limitations apply here as well. The main advantage is the ability to process many files at once without opening each one individually.
For maximum control over PDF compression settings, you can use Ghostscript through the Terminal. This command-line approach lets you fine-tune every aspect of the compression process.
First, install Ghostscript using Homebrew. If you don't have Homebrew installed, visit brew.sh to set it up, then run:
brew install ghostscript
Use the following command to compress a PDF:
gs -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/ebook -dNOPAUSE -dQUIET -dBATCH -sOutputFile=compressed.pdf input.pdf
The -dPDFSETTINGS flag controls the compression level:
This method offers the finest control but requires comfort with Terminal and command-line tools. For most users, the browser-based PDFKits approach achieves similar results with far less effort.
Here is a quick comparison to help you decide:
For the vast majority of Mac users, PDFKits Compress PDF is the recommended choice. It combines ease of use with flexible compression options and works on any Mac with a web browser.
Regardless of which method you choose, these tips will help you achieve better compression results:
Use PDFKits Compress PDF with the "Recommended" or "Less" compression level. These settings optimize the PDF structure and reduce file size while preserving the visual quality of images and text. For text-heavy documents, you can achieve significant size reduction with virtually no quality loss.
Yes, all four methods described in this guide are completely free. PDFKits is a free online tool, Preview and Automator come pre-installed with macOS, and Ghostscript is free open-source software. You don't need to purchase any software to compress PDFs on your Mac.
Open PDFKits Compress PDF in your browser, upload your file, and select the compression level that brings your file under your email provider's attachment limit. Most email services allow attachments up to 20–25 MB. For corporate email with stricter limits, use the "Maximum" compression level or try our size-specific tools like Compress PDF to 1MB.