How to Reduce the File Size of a PDF in macOS

Portable Document Format, or PDF for short, is one of the most ubiquitous file formats that is universally adopted across platforms. However, they can be quite big. Thankfully, you can reduce the file size of a PDF since macOS High Sierra. Here’s how:

Open the PDF file that you want to reduce in size. Double click it and it should open in Preview, the default PDF viewer in macOS.

Pull down the File menu and select Export.

macOS Preview app showing "Reduce File Size" menu option.

Choose the submenu next to “Quartz Filter” and choose “Reduce File Size.”

Save the new reduced version of the PDF as usual by hitting “Save.”

By the way, PDF is very useful. Invented by Adobe, it’s an open standard maintained by the International Organization for Standardization (ISO). PDFs can contain links and buttons, form fields, audio, video, and business logic. 

iPad displaying a PDF file

They can also be signed electronically (this is especially easy with an iPad and Apple Pencil). And PDF files can reliably exchanged, independent of software, hardware, or operating system.