How to crop a PDF on a Mac

With PDF Unlimited (free)

1. Open the PDF

   Open the file in PDF Unlimited and go to a page that shows the margins you want to trim.

2. Choose the Crop tool

   Select the Crop tool.

3. Drag a rectangle

   Drag a rectangle around the part of the page you want to keep. ⌘+ zooms in for a precise edge.

4. Apply it

   Apply the crop to this page only, or to all pages when every page has the same layout, like a scanned book or a slide deck.

5. Save

   Save the PDF. Made a mistake? ⌘Z undoes it before you close the file.

With Preview, built into macOS

1. Select an area

   Open the PDF in Preview, click the Show Markup Toolbar button, then click Rectangular Selection and drag over the part of the page you want to keep.

2. Crop

   Click the Crop button in the Markup toolbar. The command is also in the Tools menu.

3. Undo if needed

   Choose Edit > Undo Crop right away, or File > Revert To > Browse All Versions to go back to an earlier version later.

Good reasons to crop a PDF

Cropping changes what is visible on the page. It is handy for:

• Trimming wide white margins so text is bigger on a laptop or tablet.
• Removing the dark edges and fingers that phone scans pick up.
• Cutting a chart or figure out of a page to share on its own.
• Fitting slides or handouts onto a different paper size before printing.

Cropping hides content. It does not delete it.

This is the gotcha that matters. In a PDF, cropping usually changes the visible area of the page, called the crop box. Everything outside it is typically still in the file. Another app can reset the crop and show it all again.

So never crop to hide something private, like an account number in the corner of a statement. Use true redaction instead, which removes the content. Crop for layout. Redact for privacy.

Crop all pages, or just one?

Apply to all pages when the layout repeats, like a scanned book with the same margins on every page. Apply to one page when pages differ, such as a single landscape chart in a portrait report. If one page is sideways, rotate it first, then crop.

Apple's guide describes Preview cropping the page you have selected, so PDF Unlimited's all-pages option saves time on long documents.

Cropping and file size

Because the hidden content usually stays in the file, cropping rarely makes a PDF smaller. If size is the goal, compress it. If whole pages are unnecessary, delete them instead.

Tips for a clean crop

A few small habits give better results:

• Zoom in before dragging so the edge lands exactly where you want it.
• Leave a little margin around text. A crop that touches the letters looks cramped and can clip on some printers.
• Check a few pages after cropping all of them. Scans drift, and one page may be shifted.
• Keep an uncropped copy if you might need the full page later.

Questions