Crop PDF pages

What is "Crop PDF"?

Cropping a PDF means trimming the visible area of each page, so the parts you don't need — white borders, scanner artefacts, headers, footers — no longer display or print. The PDF spec calls this a "crop box". Crucially, the underlying page content isn't physically deleted; the crop box just tells viewers and printers which rectangle of the page to show. That makes cropping reversible: if you ever need the original margins back, the data is still there.

PDFtez gives you three ways to define the crop:

• Visual handles. Drag the corner and edge handles of the crop rectangle on the page preview. The simplest method when you want to see what you're trimming.
• Exact margins. Type margin amounts in percent, millimetres, or inches. Useful when you have a precise requirement — like trimming exactly 25 mm from every side for a print spec.
• Auto-trim white. PDFtez scans the page edges and removes any all-white border automatically. Use this for scans with uneven white margins where dragging handles would be tedious.

When to use Crop PDF

Cropping is the right tool whenever a PDF wastes paper, screen space, or attention on margins:

• Scanned documents with huge white borders. A flatbed scan of an A5 receipt on an A4 platen leaves enormous white margins. Auto-trim removes them in one click.
• Printing on smaller paper. You have an A4 PDF but need to print it on A5 or letter size. Crop to the right ratio before printing so nothing important falls off the edge.
• Mobile reading. A wide PDF with big margins forces a phone reader to zoom in. Cropping the margins makes the content fit the screen naturally.
• Removing headers and footers. Drafts often have placeholder headers ("Strictly confidential", page numbers, draft IDs) you don't want in the final file. Crop them off the top or bottom of every page.
• Print-ready trimming. Designers exporting from InDesign sometimes need to trim bleed marks before sending to print. Crop with exact mm margins to match the trim spec.
• Photo-of-document captures. A photo of a paper document taken with a phone often has fingers, table edges, or background visible. Crop tightly to the document itself.

How PDFtez crops your PDFs (under the hood)

PDFtez's Crop tool runs entirely inside your browser. When you drop a file, PDF.js renders each page to a canvas so you can see and drag your crop rectangle. When you click Save, pdf-lib updates each page's CropBox attribute — the four-coordinate rectangle that defines the visible area — and writes a new PDF in memory.

"Auto-trim white" uses PDF.js to render the page, samples the edge rows and columns for non-white pixels, and computes the tightest bounding rectangle around the actual content. It works well on clean scans of dark text on white paper; on heavily textured backgrounds it may need a manual touch-up.

No upload, no server, no logging. You can verify this in DevTools → Network while you crop.

How is PDFtez Crop different from other PDF croppers?

Most online PDF croppers (iLovePDF, SmallPDF, PDF24, Sejda) upload your file before letting you drag handles on a remotely-rendered preview. Every interaction round-trips to the server, the file lives briefly on their infrastructure, and saving requires another upload-process-download cycle. For most jobs the result is similar quality — but with all the privacy and rate-limit costs that the cloud model implies.

PDFtez does the entire operation on your device. Rendering, dragging, auto-trim, and saving all happen locally — the file you uploaded only ever existed in your browser's memory. There are no daily limits, no upgrade prompts, and the visual responsiveness is faster because every drag doesn't need to talk to a server.

Frequently asked questions

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