Wide, uneven margins show up constantly — a scanned book page with too much surrounding white space, a slide deck exported to PDF with excess padding, or a document where the content only fills the center of the page. Cropping trims the visible page area down to what you actually want, without touching the content itself.
How it works
Crop PDF shows a live preview of your first page with a draggable selection box:
- Upload your PDF.
- Drag the box over the area you want to keep.
- Preview how it looks.
- Download — the same crop is applied to every page.
The crop area is measured as a percentage of the page’s width and height, so it applies proportionally even if some pages in the file are slightly different sizes. There’s no auto-detect button that finds the margins for you and no field for typing exact inches or millimeters — you’re eyeballing it against the preview image, so zoom in first if you need the line to land in a precise spot.
Check more than the first page before you download
The live preview only renders page one — that’s the image you’re dragging the box over. If the rest of the document doesn’t line up the same way — a scanned book where later pages sit slightly off-center, a file stitched together from two different scans, a report where a few trailing pages run a different size — the same crop box can clip content on those pages that was perfectly fine on the first one. Once you download the result, actually open it and flip past the first page or two before you trust it. If something got clipped wrong further in, that’s a sign the source file isn’t as uniform as it looked, and you’re better off splitting out the mismatched pages and cropping them on their own.
One crop for the whole document
This is a single, uniform crop applied to every page — it doesn’t crop each page individually to fit its own content. That covers the vast majority of real cases, since margin issues from a scanner or export tool are usually consistent across the whole document. If you have a PDF where only specific pages need different treatment, split those out first with Extract PDF Pages, crop that smaller file separately, then merge it back.
It doesn’t reduce file size much
Cropping changes what’s visible, not the underlying embedded image or text data — so don’t expect a meaningful size reduction from cropping alone. If file size is the actual goal, use Compress PDF instead, or on top of a crop if you need both.
Don’t use this to remove sensitive information
Cropping works by setting the page’s crop box — the region that gets displayed and printed — not by deleting anything from the underlying page. Whatever’s outside your selection is still sitting in the file’s content stream; a tool or viewer that ignores the crop box can still get at it. That’s completely fine when you’re trimming a scanned margin or a slide export, but if the actual goal is getting rid of a name, account number, or anything else in the part you’re cropping away, don’t rely on crop for it. Use Hide Text in PDF instead — it rasterizes the page and paints over the marked area, so what’s underneath is actually destroyed, not just hidden from view.
Your original stays safe
The tool works on a copy of your file and only changes what’s inside the crop box on the version you download — nothing about your original file is modified, and everything happens in your browser without an upload.