Crop PDF trims the visible edges of PDF pages without redrawing or recompressing their contents. Set a margin for each side in millimetres, check the live preview, and download a new copy. The original is never changed, and the PDF never leaves your browser.
How to crop a PDF
- Drop your PDF onto the tool or click Choose file.
- Set the top, right, bottom and left margins in millimetres, or choose a preset. The preview updates as you type.
- Choose All pages or Selected pages, then click the pages you want.
- Check the resulting size and the percentage of the page that will remain.
- Click Crop and download the new PDF.
How PDF cropping works
Every page has a MediaBox, which defines the full physical page, and usually a CropBox, which defines the visible part. This tool keeps the MediaBox and writes a new CropBox inside it. Nothing is moved, scaled or re-rendered, so text stays selectable and images keep their quality.
Margins are measured from the edges of the page as you currently see it. If the PDF was already cropped, it starts from that visible area rather than revealing the larger MediaBox underneath. Millimetres are converted to PDF points: 1 mm is about 2.83 points.
The default is 10 mm on every side. Pages can differ in size, so each uses its own dimensions. Sizes shown are for the first cropped page.
Cropping versus deleting content
Cropping does not delete anything. It moves the page boundary, so everything outside the new CropBox is clipped when the PDF is displayed or printed. The content outside still exists inside the file, and an editor that can reset the crop box may reveal it.
That matters for private information. If a statement, invoice or ID document has sensitive details near the edge, cropping is not redaction and does not remove the data. Use a tool that permanently removes content before sharing. Cropping is for presentation: removing scanner borders, tidying margins or changing a page's shape. For the same reason, it rarely makes a PDF much smaller.
Page size, printing and file size
The saved page is the area left after the margins. Cropping 10 mm from every edge of A4 makes the page 20 mm narrower and 20 mm shorter, not a new paper size such as A5. Nothing is scaled; content keeps its original size and sits on a smaller page.
Printing normally follows the CropBox, so a cropped PDF prints with the new edges. Most printers cannot print to the paper's edge, so leave a few millimetres. Cropping also does not remove metadata, embedded files, bookmarks or hidden layers; use a sanitiser or redaction tool if those must go.
Rotated pages
Pages can carry a rotation of 0, 90, 180 or 270 degrees. A scan may be stored sideways and rotated only when displayed. Margins are visual: top means the top of the page as it appears in a viewer, not the top of its unrotated coordinate system.
The tool maps those margins into the page's own coordinates before writing the CropBox. On a page rotated 90 degrees clockwise, the visual top edge is the unrotated left edge, so the top margin is applied there; the visual right margin becomes the unrotated top. The preview matches your viewer's orientation.
Cropped scans and photos
Scanned pages often have black bands from the scanner lid, a strip of desk or uneven white space. Cropping those edges makes the PDF easier to read and cleaner when printed or emailed. It also helps phone scans, where the page rarely fills the camera frame.
Cropping cannot straighten a tilted scan, remove shadows or sharpen blurry text; clean the scan first if it is skewed.
A single margin may not suit every page: sheets shift as they are fed through a scanner, so a tight crop might clip a page number on one page and leave a border on another. When in doubt, leave a larger margin.
Limitations
- Password-protected PDFs cannot be opened or cropped. Enter the password in your PDF reader and save an unprotected copy of a document you own, then try again.
- Forms, links and annotations outside the kept area are still in the file but may be clipped or unusable. Bookmarks remain, though they may point to pages whose visible area has changed.
- Content outside the crop box still exists, so cropping cannot remove confidential information and is no substitute for redaction.
- Very small crops are refused. If the margins would leave less than 10 points (about 3.5 mm), reduce them rather than saving an effectively empty page.
- Large documents are held in browser memory; hundreds of pages work best on a computer.
Common uses
Cropping removes empty margins around slides before printing, trims black scanner edges, and makes a PDF easier to read on a phone, where a narrower page lets text fill the screen. It can also trim a flyer or screenshot with too much white space.
It is not for hiding a name or account number; use redaction to remove information, or delete the page entirely.
Privacy
The PDF is opened, previewed and rewritten by your browser using JavaScript. It is never uploaded to Lembog or any other server, so the tool suits private documents. There is no account or watermark. Your original is only read; the download is a new file, so you can return to the original if a crop is too tight.
Related PDF tools
- To rotate, reorder or delete pages as well as crop them, use Organize PDF.
- To remove whole pages rather than trim their edges, use Remove Pages from PDF.
- To keep only chosen pages in a new file, use Extract Pages from PDF.
- To add page numbers after cropping, use Add Page Numbers to PDF.
- To add a text or image watermark, use Watermark PDF.
- To fix sideways or upside-down pages before cropping, use Rotate PDF.
Crop PDF FAQ
Does cropping remove the content outside the crop box?
No. The content is hidden because the CropBox clips it, but it remains in the file. An editor that can reset the crop box may reveal it, so use redaction instead.
Will cropping reduce the file size?
Usually very little, and sometimes not at all. Page content, fonts and images are still stored in the file; cropping changes the visible boundary, not what the PDF contains.
Can I crop only some pages?
Yes. Choose Selected pages, then click the thumbnails you want to crop. At least one page must be selected. The remaining pages keep their current page box.
What margins should I use?
It depends. Five to ten millimetres is common for removing a thin scanner border while keeping page numbers safe. Use the preview and resulting size to judge; reduce a margin if it cuts into content.
Does cropping change the paper size when printing?
The visible page becomes smaller by the margins, and printing normally uses that new page size. Nothing is rescaled, so content stays the same size on paper. Leave a margin if your printer cannot print to the edge.
Does it work with landscape and rotated pages?
Yes. Margins follow the page as you see it, so the top margin stays at the visual top even with 90, 180 or 270 degrees of rotation. The preview matches the orientation in a PDF viewer.
Can I crop a password-protected PDF?
Not directly. The file must be unlocked before it can be read. Open it in your PDF reader, enter the password and save a copy without protection, then crop that copy.
Is my PDF uploaded anywhere?
No. The file is read, previewed and saved entirely in your browser. It is never sent to a server.