What cropping a PDF does
Scans with gray scanner borders, slides with wide white edges, a page of a report you want to show only one chart of, a receipt in the corner of an A4 or Letter scan: cropping cuts the page down to the part that matters. This tool lets you do it in your browser. Drag a box on the page preview, or type the margins in millimeters, inches or points, and save a new PDF.
- All pages or one page: one crop for the whole document, or a different crop for any page you choose.
- Exact margins: type how much to cut from the top, bottom, left and right. A PDF measures in points of 1/72 inch, and an inch is exactly 25.4 mm, so 10 mm are 28.35 points.
- Trim white margins: one click puts the box around everything that has ink on it.
- Rotated pages: you always crop the page as you see it, even when the PDF stores it sideways.
The five page boxes
A PDF page can carry up to five rectangles, defined in section 14.11.2 of the PDF standard, ISO 32000-1. Cropping changes them; the content of the page stays as it is.
| Box | What it means | When it is missing |
|---|---|---|
| Media box | The physical sheet the page is printed on | Always present |
| Crop box | The area a reader shows and prints; content outside it is clipped | Same as the media box |
| Bleed box | The area kept in professional printing, including bleed | Same as the crop box |
| Trim box | The finished page after trimming | Same as the crop box |
| Art box | The page’s meaningful content | Same as the crop box |
A plain crop sets only the crop box. Print and prepress software can position pages by other boxes, so with "Also set the page size" ticked, the tool sets all five boxes to the cropped area. The standard also says the other boxes are cut down to the media box when they reach past it, so a smaller media box keeps everything consistent.
Cropping hides content, it does not delete it
This is the part most crop tools leave out. The standard describes the crop box as the region to which the page’s contents are clipped when they are displayed or printed. Clipped content is still in the file. Text you cropped away can still be found by programs that pull text out of a PDF, and anyone with a PDF editor can reset the crop box and see the whole page again. If the cut-off area shows an account number, a signature or a name, a normal crop does not protect it.
To remove it for good, tick "Remove the hidden part for good". The tool then draws each page as an image of the cropped area only and builds a new PDF from those images, so nothing outside the box is left. The price: text can no longer be selected or searched, links and form fields are gone, and the file size depends on the resolution. You can get the same result by hand with PDF to JPG and then JPG to PDF.
Worked example
An A4 page measures 210 × 297 mm, which is 595.28 × 841.89 points. You cut 20 mm from every side. 20 mm are 20 × 72 / 25.4 = 56.69 points, so the new crop box starts 56.69 points from the left and from the bottom and is 481.89 points wide and 728.50 points high. The page now shows 170 × 257 mm.
On a page stored sideways, the same top margin lands on a different side of the stored page. A US Letter page (612 × 792 points) turned 90 degrees clockwise shows its stored left edge at the top. Cutting 0.5 inch from the top, bottom and right and 1 inch from the left gives a crop box that starts at x = 36 and y = 72 points and is 540 × 684 points, and on screen the page looks exactly as you cropped it.
How to crop a PDF
- 1Drop your PDF on the box or choose it from your device. The first page appears.
- 2Drag a box over the part you want to keep, or type the margins. Use Trim white margins for a quick start.
- 3Flip through the pages with the arrows. For a page that needs its own crop, choose "Only this page" and adjust it.
- 4If the cut-off part holds private information, tick "Remove the hidden part for good".
- 5Press Save cropped PDF. The new file downloads with "-cropped" in its name; your original stays untouched.
Pages sideways or upside down? Turn them upright with Rotate PDF first. To keep only some pages, use Split PDF, and to make the file smaller, Compress PDF.
Sources
- ISO 32000-1:2008, Document management, Portable Document Format (copy published by Adobe): 7.7.3.3 page objects (MediaBox, CropBox, Rotate), 8.3.2.3 user space (1/72 inch), 14.11.2 page boundaries
- NIST: SI units, length (the inch is exactly 25.4 mm)
Guide on this topic
Frequently asked questions
Is my PDF uploaded?
No. Your browser opens the PDF, draws the preview and saves the cropped copy on your device. Nothing is sent to a server, so scans, contracts and statements stay private.
Is the part I cropped away really gone?
No, not with a normal crop. Cropping sets the crop box, the area a PDF reader shows and prints. Text and images outside it stay in the file, and anyone with a PDF editor can make them visible again by resetting the box. Tick "Remove the hidden part for good" if the cut-off area holds something private: every page is then saved as a picture of the cropped area only.
Does cropping make the PDF smaller?
Hardly. A normal crop only changes a few numbers in each page, and all content stays in the file, so the size stays about the same. To shrink the file, use Compress PDF. With "Remove the hidden part for good" the size depends on the pages and the resolution, and can go up or down.
Can I crop pages differently?
Yes. Choose "Only this page" above the margins, and the crop box you set applies to the page you see. Go to the next page and do the same. Pages without their own crop use the crop for all pages.
Why does the crop not show in another program?
Some programs, mostly print and prepress software, place pages by their trim box, bleed box or media box rather than the crop box. Leave "Also set the page size" ticked: the tool then sets all five page boxes to the cropped area, so every program sees the same page.
Do rotated pages crop correctly?
Yes. You crop the page the way it looks on screen. The tool reads how each page is turned and converts your margins to the page’s own coordinates, so the top margin is always cut from the top you see.
What does "Trim white margins" do?
It looks at the preview of the page you see, finds the area that has any ink on it and puts the crop box around it, with about 2 mm of space left. Check the result on a few pages before you apply it to all of them, because scans often have specks or shadows near the edges.