Crop PDF
Trim margins from PDF pages, manually or automatically.
Choose PDF file
or drop it anywhere on this page
PDF
Processed on your device — never uploaded
How to crop pdf
- Open a PDF.
- Choose manual margins or auto-detect whitespace.
- Preview the crop boundary, then apply and download.
About this tool
PDFs from scanners often have fat margins from the scanner glass. PDFs from presentation software print with huge slide borders. Cropping is the quickest way to get the content to fill the page.
Auto-detect handles most cases without any measurement: it renders each page and finds where the white ends. Manual mode is there for asymmetric margins, or when the document has a light-grey background that confuses the threshold. Either way, the original content is not deleted — just hidden outside the crop boundary, as is standard across all PDF viewers.
Questions
Does cropping permanently remove the content outside the crop box?
No. PDF cropping works by setting a CropBox, which hides the content outside it from viewers. The content is still in the file — it is just not shown. This is the standard PDF behaviour and is how all crop tools work, even in professional software. If you genuinely need the outside content removed, you would need to re-render the pages, which requires server-side tools.
Why are margins measured in points rather than millimetres or pixels?
PDF coordinates are defined in points (1/72 of an inch), which is what the underlying format uses. One point is approximately 0.353 mm. A 25 mm margin is about 71 pt.
How does auto-detect work?
Each page is rendered to a bitmap in the browser and scanned inward from each edge until non-white pixels appear. The detected boundary becomes the CropBox. It works well on white-background documents; scanned pages with off-white backgrounds sometimes need the threshold adjusted.