How to crop PDF pages, and why cropping is not the same as redacting
Trim margins and scanner borders from a PDF with a live preview, and learn why cropped content is still in the file and how to really remove it.
A scanned page comes out with a thick black border from the scanner lid. A report has wide margins that waste space when you print it or read it on a phone. A form has a header you do not want in the copy you send. Cropping the pages of a PDF fixes all of these, and it is simple once you know a few details.
Crop a PDF in your browser
- Open Crop PDF Pages and add the PDF.
- Choose a unit: millimetres, centimetres, inches or a percentage of the page.
- Enter how much to trim from the top, bottom, left and right. By default the four sides stay the same, which suits even margins. Untick “Same amount on all four sides” to trim each edge separately.
- Watch the preview. The shaded area is what will be removed, and the bright outline is what remains. Use the preview-page box to check other pages.
- To crop only some pages, type a list such as
1-3, 5. Click Crop & download.
The margins are measured on the page as you see it. That matters for scanned documents, which are often stored rotated. The tool turns your top, bottom, left and right to the correct edges, so the preview and the result agree.
Handy amounts to try
| Goal | What to do |
|---|---|
| Remove a scanner’s dark border | 3 to 8 mm on all sides, then check the preview for any remaining edge |
| Read a report on a phone | 15 to 20 mm left and right, so the text fills more of the screen |
| Drop a page header or footer | Trim only the top or only the bottom, by the height of the header |
| Remove a letterhead from page 1 only | Enter the amount for the top, and limit the pages to 1 |
Important: cropping hides, it does not delete
Never use cropping to hide private information. Cropping changes what is visible on the page, but the content outside the visible area is still stored in the file. Anyone with the right software can reveal it.
If a document contains something you must remove, such as a name, an account number or a photo, cover it with a solid black box and then flatten the page into a picture, so the original content no longer exists in the file. One way:
- Turn the pages into pictures with PDF to Images.
- Blank out the sensitive parts with Blur & Redact, using the black box option.
- Rebuild the PDF with Images to PDF.
The result is a PDF of pictures, so its text can no longer be selected, but the hidden details really are gone. The guide to blurring and redacting explains which effect is safe.
Cropping and file size
Cropping does not shrink a PDF, because the hidden content stays in the file. If size is the problem, use Compress PDF, as described in how to reduce PDF file size. Crop first and compress last, so the final step does not have to be repeated.
Different amounts for different pages
The tool applies one set of margins to the pages you select. For different amounts, run it more than once: crop pages 1-3 with one set of values, download the result, upload it again and crop the remaining pages with another.
The document is processed in your browser and never uploaded, which is worth knowing for scanned IDs and certificates. See Are online file converters safe?.