Crop PDF

How to use the Crop PDF tool

1. Choose your PDF. The first page appears as a preview.
2. Drag a box around the part you want to keep, or switch to margins and type millimetres.
3. Choose the pages: all of them, or a range.
4. Press Crop and download the result.

What cropping a PDF actually changes

Every PDF page carries two rectangles that matter here. The media box is the physical size of the sheet. The crop box is the part a reader displays. Cropping sets a smaller crop box, so readers show less of the page - and that is all it does.

Because nothing is re-drawn, the page keeps everything it had. Text is still text and still searchable, vector drawings stay sharp at any zoom, and images are not re-compressed, so there is no quality loss whatsoever.

If you also tick "trim the page size", the media box is moved to match. Printers and other software then treat the page as genuinely smaller, which is what you want when the file is going to a print shop or being placed into another document.

Cropping does not delete anything

This is the one thing to be clear about. The content outside the crop box is still in the file. A reader can set the box back, and software that ignores crop boxes will show the whole page.

That is fine for the usual reasons people crop: removing the white border from a scan, cutting the printer's crop marks off a proof, trimming a slide handout down to the slide. In all of those cases the hidden part is simply blank or irrelevant.

It is not fine if the point is to hide information. If there is a name, an address or an account number outside the box that must not be recoverable, use Redact PDF instead - it rasterises the page so the content is genuinely gone. We say this plainly because the opposite assumption has caused real leaks in published documents.

Dragging a box, or typing margins

Dragging is quicker when you can see what you want. The first page is rendered as a preview, you drag a rectangle, and a readout shows what proportion of the page you have kept. The box is stored as a fraction of the page, so it applies correctly to every page you choose regardless of its size.

Typing margins is better when you need to be exact or consistent. Give the top, bottom, left and right in millimetres and exactly that much is trimmed from each side - the right approach when several documents must end up identical, or when a print shop has asked for a specific trim.

Rotated pages are handled correctly. If a page was saved rotated, the preview shows it as you see it, and the box you drag is translated back into the page's own coordinates before being applied.

One page, a range, or everything

Applying the same crop to every page is the common case, because the pages of a scan or an export all have the same margins.

A range is useful when a document changes shape partway through - a report with landscape tables in the middle, or a scan where the first page was fed in differently from the rest.

Pages you do not include are copied across untouched, so you can crop in two passes with different boxes if a document really needs it.

Why people crop PDFs

Scanned pages are the biggest reason. A scanner set to A4 and fed a smaller sheet produces a page with a white band down one side, and on a phone or e-reader that band wastes a third of the screen. Cropping it away makes the document genuinely easier to read.

Presentation handouts are the second. Slides printed four to a page come back with headers, footers and frames nobody wants; cropping to the useful area turns them into something you can reuse.

Then there is the practical business of fitting a page into something else: a figure for a paper, a map for a report, a form that must sit inside a fixed frame. Cropping gets the page to the right shape without touching the content.

Nothing is uploaded

Files are not uploaded - everything happens in your browser. The PDF is parsed here, the preview is rendered here, and the cropped copy is written in memory before going to your downloads folder.

Two libraries are needed - one to render the preview and one to write the new file - and both are fetched on demand after you choose a file, then cached.

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