PDFs arrive with wasted space more often than they should: scans with a black gutter down one side, articles with enormous journal margins, slides exported with a border of empty white. Cropping trims the visible page down to the region that matters, which makes the document far more readable on a phone or tablet where every wasted millimetre costs legibility.
This tool works by setting the PDF CropBox. You draw a rectangle on the first page and the same proportional region is applied to every page in the document, so a consistent margin is trimmed throughout rather than page by page.
The crop is applied by pdf-lib inside your browser. Journal articles, contracts and internal reports are never uploaded to be processed.
-cropped suffix.This is worth understanding clearly. A PDF page has both a MediaBox, the full sheet, and a CropBox, the portion a reader displays. Setting the CropBox tells viewers to show less; the content outside it is still present in the file. Anyone can restore it by resetting the CropBox in a PDF editor.
That behaviour is a feature when you are tidying margins — nothing is destroyed and the change is reversible. It is a serious problem if you are cropping to hide sensitive information. Never use cropping to redact. To remove content permanently, convert the pages to images with PDF to JPG and rebuild the document from those, which discards everything outside the visible area for good.
No. It sets the CropBox, which changes what viewers display while leaving the underlying content in the file. Anyone with a PDF editor can undo it.
No, and doing so is unsafe. Cropped-away content remains recoverable. To remove it permanently, convert the cropped pages to images with PDF to JPG and rebuild a PDF from those images.
No. One rectangle is applied proportionally to every page, which is what you want for consistent margins. To crop pages differently, split the document first, crop the parts separately and merge them back.
The rectangle is stored as a proportion of the first page, then scaled to each page’s own dimensions. Pages of different sizes therefore get an equivalent relative crop rather than an identical absolute one.
Yes. Nothing is rasterised — only the page boxes change — so text, links and vector graphics are all preserved exactly.
No. PDF.js renders the preview and pdf-lib writes the new page boxes, both in your browser. The file never leaves your device.