A PDF with an inch of dead white space around every page isn't just annoying to read on a phone screen -- it also wastes paper if you print it and makes a scanned document look unnecessarily amateur. Cropping fixes that by trimming the margins down to whatever you actually need. LockerPDF's Crop PDF tool does this entirely in your browser, with a visual crop box you can drag over the page, and the file never leaves your device.
What cropping a PDF actually changes
Every page in a PDF has a defined visible area -- its CropBox -- which is what PDF viewers and printers use to decide what part of the page to display. Cropping doesn't redraw or delete any content; it adjusts that visible boundary so that whatever falls outside it is no longer shown. Think of it as trimming a photo rather than repainting it: the underlying page content stays where it is, but the frame around it gets smaller. This matters because it means cropping is non-destructive to the page's actual text and images -- it just changes what part of the page is presented.
How to crop a PDF online without uploading it
- Go to the Crop PDF tool and upload the PDF you want to trim.
- A preview of the first page appears with a crop box overlaid on it. Drag the box itself to move it, or drag one of its four corner handles to resize it.
- If you need exact measurements instead of eyeballing it, type values directly into the top, bottom, left, and right fields -- these are in points, where 72 points equal 1 inch.
- Click "Crop PDF." The tool applies the same margins to every page in the document.
- Download the cropped file.
Because the crop is applied uniformly to every page, this works best for documents where the margins are consistent throughout -- a scanned book, a report exported from the same source, a set of slides. If different pages have very different amounts of white space, crop conservatively enough that you don't clip content on the pages with less margin to spare.
Common reasons people crop a PDF
- Scanned documents with wide borders. A page scanned slightly askew or from a larger source often ends up with lopsided white space around the actual content -- cropping tightens it up.
- Reading on a small screen. Trimming dead margins means more of the actual page fills a phone or e-reader screen when you zoom in.
- Printing without wasting paper or ink on blank space. Tighter margins mean the printed page uses more of the sheet for content.
- Removing a header, footer, or watermark strip. If unwanted content sits consistently along one edge of every page, cropping that edge down removes it from view.
Cropping vs. other ways to trim a PDF
Cropping is not the same as deleting a page -- for that, use Organize PDF, which lets you rotate, delete, and reorder individual pages instead of adjusting their visible area. And if what you actually want is an image of a specific region of a page rather than a trimmed PDF, converting the page with PDF to JPG and cropping the resulting image in any photo editor is often a more precise route for pulling out a single figure or table.
How to verify nothing is uploaded
Open your browser's developer tools (F12), switch to the Network tab, and crop a file. You'll see no outgoing request carrying your document's data -- cropping happens in your browser tab using JavaScript, the same way it would if you were running the tool entirely offline.
FAQ
Are my files uploaded anywhere when I crop them?
No. Cropping runs entirely in your browser using JavaScript -- the PDF is read from your device, its CropBox is adjusted in memory, and the result is handed back to you as a new file. Nothing is transmitted to a server.
Does cropping permanently delete the content outside the margins?
Not in the sense of redrawing the page -- it adjusts the page's CropBox, the boundary that viewers and printers use to display it. This is what most PDF crop tools do, and it's sufficient for hiding margins from anyone opening the file normally, but it isn't a redaction technique for content you need permanently destroyed.
What unit are the margin values in?
Points, the standard PDF measurement unit. 72 points equal 1 inch, so a half-inch margin is 36 points.
Can I crop each page differently?
No -- the crop margins you set are applied equally to every page in the document. If your PDF has pages with very different layouts, crop conservatively so you don't clip content on the pages with the least margin.