Trim unwanted white margins, header boilerplate, and footer numbers from your PDF documents with our free PDF Cropper. Specify custom margin offsets in 72 DPI point coordinates for top, right, bottom, and left page boundaries. Apply uniform crops across all pages instantly inside browser RAM with 100% privacy and zero server file uploads.
Load your PDF document into the visual canvas cropping area.
Adjust crop bounding boxes to trim white page margins, headers, or unwanted borders.
Click Crop PDF to update MediaBox dimensions and save your trimmed document.
Trim unwanted margins, white borders, and header/footer boilerplate uniformly across every page in your document.
Specify exact top, right, bottom, and left margin offsets using standard PDF point units (72 points = 1 inch).
All CropBox dictionary updates execute directly inside client RAM using pdf-lib. Zero files are uploaded to remote servers.
PDF specifications define page boundaries using four main rectangle coordinate arrays: /MediaBox (the overall physical medium size), /CropBox (the visible region displayed on screen or printed), /BleedBox (print production clipping), and /TrimBox (intended finished page size).
When cropping a PDF, the client-side JavaScript engine modifies the /CropBox array [xLowerLeft, yLowerLeft, width, height] for each page dictionary using page.setCropBox(left, bottom, width - left - right, height - top - bottom). This instructs PDF viewers (such as Adobe Acrobat or Google Chrome) to clip content outside these coordinates.
Because this operation updates dictionary entries directly inside client RAM, vector paths, fonts, and embedded images are never rasterized or degraded, preserving 100% original document quality while trimming page borders.