CropBox & MediaBox
Two of the PDF boxes that define what part of each page is visible and printable — the MediaBox is the physical page, the CropBox is the visible window.
Every PDF page is defined by several rectangles called "boxes," each with a specific purpose. The two most important for everyday use are the MediaBox and CropBox.
The five PDF page boxes
- MediaBox — the *physical* page size. The full extent of the page as it would be printed on paper. Every PDF page must have a MediaBox.
- CropBox — the *visible* region when the PDF is displayed or printed. Content outside the CropBox is clipped in viewers. Defaults to the MediaBox if not set.
- BleedBox — the area including bleed (ink extending past the trim edge) for commercial printing
- TrimBox — the intended final size after trimming in professional print
- ArtBox — the extent of meaningful content, used in art / design workflows
For most users, MediaBox and CropBox are the only two that matter.
Cropping a PDF — two approaches
When you "crop" a PDF, there are two ways to do it:
1. Change only the CropBox — the content outside is still there in the file, just hidden by most viewers. Useful if you might want to restore the original page later.
2. Change the MediaBox too — the page is *actually* smaller. Content outside the new boundary is effectively gone for normal viewers.
PDF Genie's Crop PDF tool modifies both the MediaBox and CropBox so the crop is permanent for all viewers and uses.
Why this matters
- Print shops care deeply about BleedBox and TrimBox — getting them wrong leads to white borders or content being trimmed off
- Screen-only readers care only about CropBox — that's the visible region
- Automated processors may look at different boxes depending on how they were written — leading to subtle differences in behavior when the boxes disagree
Tools
- Crop PDF — trim page edges by adjusting MediaBox and CropBox
- Resize PDF — change the page dimensions while rescaling content to fit