How to make a PDF smaller on a Mac with Preview

2 min read · 5 steps · Updated 2 October 2026

A scanned form or a brochure with photos can be far too large to email or upload. Preview, the PDF viewer that comes with every Mac, can shrink it in a few clicks. The saving comes almost entirely from the images, so a PDF that is only text will hardly change.

Menu names are from recent versions of macOS, where the settings app is called System Settings.

Step by step

1. Open the PDF in Preview

   Double-click the file. If it opens in another app, Control-click it and choose Open With, Preview.

   Done

2. Choose File, Export

   Not Export as PDF, which has no compression options.

   Done

3. Tick the compression options

   Optimize images for screen reduces the resolution of the pictures to what a display needs. Save images as JPEG converts all pictures to JPEG. You can tick one or both. On older versions of macOS the same job is done by the Quartz Filter menu with the entry Reduce File Size.

   Done

4. Give it a new name and click Save

   Use a different name, so the original stays untouched.

   Done

5. Check the result

   Open the new file and zoom in on small print and on photos. Apple notes that a compressed PDF may be of lower quality than the original. Compare the sizes in Finder with Command + I.

   Done

Good to know

If the text in a scan becomes hard to read, try again with only one of the two options.

For finer control over the quality, our free tool works in the browser without uploading the file: compress PDF.

Removing pages you do not need saves more than any compression: open the sidebar with View, Thumbnails, select pages and press Delete.

More with Preview: how to combine PDF files on a Mac and how to sign a PDF on a Mac.

In short: Preview, File, Export, tick Optimize images for screen and/or Save images as JPEG, new name, Save, check the quality.