How to crop a PDF
- Drop the PDF. The first page appears as a preview.
- Drag a box over the part you want to keep, or type the margins to cut off in millimetres. The kept part stays bright, the rest is darkened.
- Choose Every page the same or Only this page, and use the arrows to check other pages.
- Press Crop PDF and download it.
Margins typed in millimetres are applied in millimetres on every page, so a document that mixes A4 and Letter pages, or has a page turned sideways, loses the same strip everywhere. A box drawn with the mouse is applied in proportion to each page.
Trim the white margins automatically
Trim white margins looks at each page separately and crops it to where the content starts and ends, leaving a thin border. This is the quick way to make a scanned book or a paper with wide margins readable on a phone, tablet or e-reader, where every millimetre of margin makes the text smaller. Because each page gets its own crop, a chapter opening that starts halfway down is not squeezed to fit the others. Blank pages are left as they are. Page numbers, headers and faint lines near the edge count as content, so look through the pages before saving.
Cropping hides, it does not delete
A PDF crop changes the visible area of the page. Everything outside it is still in the file: anyone can copy it, search it, or reset the crop in a PDF editor and see the whole page again. We tested this with a three-page A4 document that had an account number in the header and a page footer, cropping 40 mm off the top and bottom (Chrome on Windows, 18 October 2026):
| Crop | Cut-off text still in the file | File size |
|---|---|---|
| Normal crop | Yes: 1,309 characters across the three pages, including the account number, which a standard PDF library (pypdf) printed straight back out | 3.4 KB, the same as before |
| Delete what is cut off for good | No: the word did not appear anywhere in the file’s bytes | 773 KB |
That is why the result tells you how many characters of text lie outside your crop. If the cut-off part holds anything you don’t want to share, tick Delete what is cut off for good. The cropped pages are then redrawn as 200 dpi images that contain only the part you kept, in a new file. The price: their text can no longer be selected or searched, links on them stop working, and a text-only PDF becomes much larger, as the table shows. For blacking out a few words inside the page rather than cutting the edges off, cropping is the wrong tool altogether.
Why the cut-off parts stay hidden everywhere
A page in a PDF has several boxes. Many tools only move the crop box, which viewers respect, but some printing paths and programs size the page by the media box, the full sheet, and show the cut-off parts again. This tool sets both to the area you chose and removes the old trim and bleed boxes, so the page is the same size in every viewer and prints at that size. Links, bookmarks and form fields inside the kept area keep working.
Related: to change pages to A4 or Letter without cutting anything, use Resize PDF Pages; to remove whole pages, Delete PDF Pages; to split two-page scans down the middle, Split PDF. Everything runs in your browser: the PDF is not uploaded.