Crop PDF

What this tool does

Crop PDF trims the edges of PDF pages. Enter margins for each side or let the tool detect the white space around the content of every page, check the shaded preview, and save a PDF with a new crop box and page size.

Wide margins waste space on phones and e-readers, where every millimetre of screen counts, and scanned pages often have dark borders or a strip of the next page along the edge. Cropping removes those areas so the content fills the view or prints larger.

The tool changes the page boxes that define the visible area of each page. With Fixed margins you enter how many millimetres to remove from each side; with Trim white space each page is rendered with pdf.js, the first and last non-white pixels are found, and the crop is set around that content plus the padding you choose. pdf-lib then writes the new CropBox and, if you keep the option on, the MediaBox, TrimBox and BleedBox as well. Your file stays on your device.

How to use Crop PDF

1. Drop a PDF onto the upload area. The first page appears in the preview.
2. Choose a Method: Fixed margins or Trim white space.
3. For fixed margins, enter Top, Bottom, Left and Right values in millimetres, or press Use detected margins from this page.
4. Set Padding around content to keep a little breathing room around the text.
5. Use the page arrows to check other pages; the shaded areas show what will be removed and the new size is shown below.
6. Optionally limit Pages to a range, then press Crop PDF and download.

Tips for better results

• Trim white space treats each page separately, ideal for scans where the content shifts from page to page.
• For a book scan with a dark gutter on one side, use fixed margins with a larger value on that side.
• Keep Also resize the page switched on; otherwise the removed area is only hidden and may reappear in some editors or when printing.
• Lighter grey backgrounds count as content when darker than about 94 percent brightness. Increase the margins manually if a faint scan border remains.

Common use cases

• Making academic papers easier to read on a small tablet by removing wide margins.
• Removing black scanner borders from digitised documents.
• Cutting a single figure or chart out of a page for a presentation.
• Trimming printer marks from a print-ready PDF for on-screen viewing.

Common mistakes to avoid

• Entering margins larger than the page, which would leave nothing visible. Such pages are skipped and reported.
• Expecting the file to become smaller. Cropping hides content outside the box but does not delete it.
• Relying on cropping to remove sensitive information. Hidden content can be recovered; use a redaction tool for that.