How to Trim the Margins on Every Page of a PDF

Here's the actual process for trimming a PDF's margins with Crop PDF, from the dropped file through to the cropped download.

Step 1 - drop the PDF

Choose or drag in the file, up to 80 MB, with no page-count limit. A page-1 preview appears with a crop-region overlay already drawn on it, using the default margin, so there's something real to look at immediately rather than a blank options panel.

Step 2 - adjust the four margin sliders

Top, right, bottom, and left, each independently, each running from 0 up to 45% of that side's own dimension. The default on every side is 5%, a modest trim that's easy to see the effect of without overcommitting. As a side is dragged higher, the overlay on the preview updates immediately, so the crop is visible before it's applied to anything. One safety rail worth knowing about: a pair of opposite margins (top+bottom, or left+right) is capped so their combined total can't exceed 90% - a real guard against accidentally cropping a page down to nothing by dragging both sides to their individual maximum at once.

Step 3 - one setting for the pages you crop, scaled automatically

The percentages you set apply to every page you crop in a single pass. By default that is the whole document; the Which pages section narrows it - type 2-12, or 1-3, 7, 10- where 10- means page 10 to the last page, or tick the box to leave the first page alone, and every page you don't list is copied through untouched. There's no per-page crop amount, and that's deliberate: a document is usually meant to look consistent page to page, not trimmed by eye on each one individually. If the PDF mixes page sizes (a cover page in one format, body pages in another, which happens more often than expected in exported documents), each page's margin is calculated as that percentage of its own dimensions, not a fixed point size copied from a different page - so a 5% top margin trims 5% of each page's actual height, whatever that page's height is.

Step 4 - crop and download

Once the overlay looks right, click Crop and the trimmed PDF downloads. Under the hood, the tool sets the PDF's own crop box and media box for every page to the smaller rectangle you defined - the same mechanism PDF viewers use to decide what area to actually display.

What this does not do

Cropping is a display change, not a deletion. Setting a page's crop box smaller tells a PDF reader to show less of the page - it doesn't remove, redraw, or delete anything from the underlying content stream. Anything that used to sit in the trimmed margin - a header, a stray mark, a sliver of something you meant to cut off entirely - is still physically present in the downloaded file, just outside the area a normal viewer displays. This guide covers exactly what that means if you're trying to hide, not just trim, something.

If a margin looks too aggressive after cropping

Dragging a single side too high before checking the preview is the easiest way to end up trimming into content that was never meant to be cut - the 45%-per-side ceiling and the 90%-combined-pair cap exist specifically to stop the extreme version of this, a page cropped down to almost nothing, but they don't stop a more modest over-crop that still clips a line of real text. The overlay on the preview is drawn against the actual page-1 content precisely so this is visible before it's applied to the rest of the document, not discovered afterward in the downloaded file. If a margin looks wrong, it costs nothing to drag it back down and check again - nothing is committed until Crop is clicked.

Nothing here goes to a server

The PDF you drop and the cropped file you download both stay inside the browser the whole way through - there's no upload step, and the only limit is the 80 MB file cap, set to stay inside your browser's memory.

For why scanned and exported PDFs end up with such wide margins in the first place, see the background. Or crop a PDF now.