How to Crop the Margins of a PDF (and What Cropping Doesn’t Remove)

How to crop a PDF

1. Open Crop PDF and choose your file.
2. Enter how much to trim from the top, right, bottom and left, in millimetres.
3. Leave Pages as “All”, or list the pages to crop — for example 1-3, 7.
4. Download and check the edges of every cropped page.

The important part: cropping hides, it doesn’t delete

A PDF page has a “crop box” that sets which part of the page is shown. Cropping changes that box — it doesn’t delete what’s outside it. The trimmed content is still inside the file, and anyone with a PDF editor can reset the crop box and see it again.

That makes cropping perfect for tidying up, and never suitable for removing private information. If you need to get rid of an account number in the margin, a name in a header or anything else sensitive, use Redact PDF, which permanently removes the content. See how to redact a PDF properly.

Good reasons to crop

• Scanner borders and shadows around scanned pages.
• Large white margins on slides or e-books that make text small on phones and tablets.
• Receipts and small documents scanned on a full A4 page.
• Consistent margins across a document assembled from several sources.

Cropping a whole document vs. some pages

If every page has the same border — slides, or pages from one scanner — crop them all with the same values. If only a few pages need it (a couple of scanned inserts in a digital report), list those pages only. Mixing cropped and uncropped pages is fine; cropped pages simply display smaller in viewers that fit pages to the window.

Measuring how much to trim

An A4 page is 210 × 297 mm and US Letter is 216 × 279 mm. Standard document margins are 20–25 mm. Scanner borders are usually 3–10 mm. If you want to trim a scanned receipt that occupies the top-left of an A4 page, measure roughly on screen: if it covers about half the width and a third of the height, trim around 100 mm from the right and 190 mm from the bottom, then fine-tune.

Cropping and page size

Cropped pages become smaller pages. When printed with “fit to page”, the content is enlarged to fill the paper — often what you want for receipts and slides. With “actual size” printing, the cropped page prints at its original scale with blank paper around it. Page numbers and watermarks added afterwards with Add page numbers and Watermark PDF are positioned within the cropped area, so crop first and number last.

Crop PDF vs. cropping an image

If you need the trimmed area genuinely gone and the page is essentially a picture — a scanned certificate, say — another option is to save the page as an image with PDF to JPG, crop it with the Image Cropper, and turn it back into a PDF with JPG to PDF.

Worked example: tidying a scanned tax bundle

Grace scanned 18 pages for her accountant on a flatbed scanner. Each page has a dark 6 mm strip along the top and left where the lid didn’t close, and three of them are small receipts sitting in the corner of an otherwise empty A4 page.

1. She rotates two sideways receipts first with Rotate PDF.
2. In Crop PDF, she trims 8 mm from the top and left of all pages — enough to clear the dark strips without touching the content.
3. She crops the three receipt pages separately, trimming the empty space so each receipt fills its page.
4. She checks every page, then adds page numbers so her accountant can refer to “page 12”.

One of the receipts showed her full card number in the corner. Instead of cropping it out — which would have left it in the file — she redacted it.

Cropping is reversible in the same way: the original page area is still there, so a PDF editor can restore it if you trim too much. Keep your original file anyway.

Cropping and file size

Because the hidden area is still stored, cropping doesn’t make a file noticeably smaller. If size is the problem, use Compress PDF; if hidden content is a concern, redact instead of cropping, or rebuild the page as an image as described above, which genuinely discards what’s outside the crop.

Cropping slides and e-books for reading on a phone

Presentation PDFs and exported books often carry wide margins designed for printing. On a phone, those margins make text small enough to need zooming on every page. Trimming 10–15 mm from each side of every page makes the content fill the screen, and a “fit width” view then gives you noticeably larger text. Keep the original file too — cropped pages printed at actual size will have uneven blank borders.

Why cropped pages may look different sizes

If you crop some pages and not others, viewers that fit each page to the window will show the cropped pages larger. That’s expected. If you want a consistent look — for example, receipts in a bundle — crop them to similar proportions, or put them on standard pages instead: save each as an image with PDF to JPG and rebuild the bundle with JPG to PDF on A4 with a small margin, which gives every page the same size.

Checking the result

• Look at each page edge at 100% zoom — nothing important should touch the edge.
• Check the first and last pages of each section, where headers, footers and page numbers usually sit.
• Print one page if the document will be printed, to see how your printer handles the smaller page size.

Common mistakes

• Using cropping to hide sensitive details.
• Trimming too much and losing page numbers, footnotes or stamps near the edges.
• Cropping before rotating, so the values apply to the wrong edges.
• Cropping decorative borders on certificates, which can make official documents look altered.

Privacy

Cropping runs in your browser, so the documents aren’t uploaded.