Open your PDF file in Preview, generally speaking, it is the default PDF viewer on your mac.Though it requires no installation and cost to shrink PDF on mac with Preview, it cannot batch process multiple PDFs file at the same time.įollow the steps to Reduce PDF File Size on Mac with Preview. Preview is the free tool coming with MacOS to manage PDF files and images, you can utilize Preview to open, crop, print and edit supported files, also you can use Preview to reduce PDF file size on mac easily. How to Reduce PDF File Size on Mac with Preview How to Reduce PDF File Size on Mac without Preview.How to Reduce PDF File Size on Mac with Preview.