How to crop PDF pages on a Mac
By Himanshu Ranjan · Updated 8 November 2026
To crop a PDF on a Mac, use Preview's Rectangular Selection and the Crop button, or select the file and run Pages › Crop margins in FileDial to trim white margins automatically. Pages › Crop margins by size… hides margins by amounts you set. Both save locally.
Crop in Preview for one page
Apple's steps: open the PDF, show the Markup toolbar if it is hidden, click the Rectangular Selection button, drag over the part of the page you want to keep, and click the Crop button. To see the selection's dimensions, choose Tools › Show Inspector and pick a unit. To undo right away, use Edit › Undo Crop, or later File › Revert To › Browse All Versions.
This is the right method when you want one particular area, such as a single table or a figure. Preview crops the pages you have selected, so check in the thumbnail sidebar that you are cropping the pages you intend.
Crop margins automatically with FileDial
Scans and exported pages often carry wide white borders. Pages › Crop margins trims white margins, and per its note nothing is deleted. That last point matters: the content outside the new visible area stays in the file, so the crop is reversible in principle but also means hidden content is still there.
- Select the PDF in Finder.
- Hold the right Option key to open the dial and choose the Pages category.
- Release on Pages › Crop margins.
- Open the new copy and flick through; check that pages with small content did not shrink too far.
Set exact margins
When you need the same crop on every page, such as a fixed margin for a printer or e-reader, use Pages › Crop margins by size… It hides the margins by the amounts you choose, and again nothing is deleted. Use a small amount first and look at the widest-content page, because a margin that is right for page 1 can clip a table on page 7.
- Uneven scans: Crop margins (automatic).
- Same trim on every page: Crop margins by size…
- One area from one page: Preview crop.
- Fit a standard paper: Pages › Resize to A4 or Resize to Letter.
A worked example: a scanned workbook with fat margins
Say a 30-page textbook chapter was scanned flat on a glass bed, so each page has a two-inch white frame and the text sits small in the middle. Run Pages › Crop margins, open the copy, and the text fills the screen. Check the pages with figures near the edge, because the automatic trim follows the content and a stray speck in a margin can make a page look as if it has content there.
If a few pages resist, split the job: crop all pages with Crop margins by size… using a small, safe amount, then fix the stubborn pages in Preview with a rectangle. Two passes with different tools is often quicker than hunting for one setting that fits every page. Keep the original scan; cropping is a presentation choice and you may want the full page later for printing.
Cropping hides, it does not remove
A cropped PDF usually keeps the outside of the page; the crop only changes what is visible. That is good for undoing a mistake and bad for privacy. If you cropped out a name, a barcode or a signature to share a page, assume someone can restore it with the right tool.
If the content must truly be gone, redact instead and check the result. Our guide to redacting a PDF properly explains why covering or cropping is not enough.
Cropping and file size
Cropping does not shrink a PDF's file size in itself, because the content outside the visible area is kept. People are often disappointed to crop a heavy scan and see no savings. If you want a smaller file, compress separately: Compress › Compress PDF keeps text selectable while images go to 144 dpi, and Compress › Compress PDF (strong) goes to 96 dpi for screen-only use.
For a scan that will be printed, use Compress › Compress PDF (light) at 200 dpi. Higher resolution matters more for print than for screens; the dots-per-inch figure describes how many dots fit in an inch, so fewer dots means a softer print.
For scanned books, cropping the margins makes text larger on a phone or e-reader, which is why people do it. If pages are tilted, straighten first with OCR › Straighten scanned pages…, then crop, because a tilted page makes the automatic trim cut into the text.
If you plan to read on an e-reader, Convert › PDF to EPUB makes a reflowable e-book instead, where pages without text become pictures. Reflow suits novels; cropping suits fixed-layout pages like textbooks.
Check the result
Look at the first, last and one middle page. Confirm page numbers, footnotes and any marginal notes are still visible, and that two-page spreads did not lose their gutter. Resizing paper is a different job: use Pages › Resize to A4 or Resize to Letter, noting that links and form fields are flattened by those tools.
Cropping scans of IDs or statements is common, and those are the files not to upload. FileDial crops on your Mac and writes a copy beside the original.
Questions
Does cropping a PDF delete the cropped area?
Usually not. FileDial's Pages › Crop margins and Pages › Crop margins by size… state that nothing is deleted, so the hidden area stays in the file and can be recovered. If something sensitive must really be gone, redact it instead of cropping.
Can I crop every page of a PDF the same way?
Yes. Select the PDF and run Pages › Crop margins by size… with the amounts you want, or Pages › Crop margins to trim white margins automatically. Check a page with wide content first so you do not clip a table or a figure.
How do I crop just one page in Preview?
Open the PDF, select that page's thumbnail, choose Rectangular Selection in the Markup toolbar, drag over the area to keep and click Crop. If it is wrong, choose Edit › Undo Crop straight away, or use File › Revert To › Browse All Versions later.