Crop a PDF online
Drag a crop box over any page and trim white margins from a whole PDF at once. Lossless — text stays selectable. No upload, no limits.
- Runs in your browser
- Files are never uploaded
- Free, no account
Your PDF never leaves this tab — here is how to check
This page has no upload step and no server behind it. Two ways to confirm that yourself, neither of which requires trusting us:
- Turn off Wi-Fi or put the device in aeroplane mode after this page has loaded, then run the tool. It still works.
- Open your browser’s developer tools, switch to the Network tab, clear it, and process a file. No request appears.
The reason this matters: in 2025 the PDF service pdf.net was found exposing roughly 3.5 million user-uploaded documents, and formatter sites JSONFormatter.org and CodeBeautify leaked over 80,000 saved snippets containing live cloud credentials. Those are architectural failures — a file that is never sent cannot be exposed that way.
How to crop a PDF
- Drop the PDF above. The first page renders straight away and becomes the canvas you drag on.
- Drag the blue rectangle to the area you want to keep, or press Auto-detect margins to snap it to the ink on the page.
- Prefer numbers to dragging? Type the trim in millimetres for each edge instead — the two controls stay in sync, so the whole tool is usable from the keyboard.
- Step through pages to check the crop suits the rest of the document, choose whether it applies to all, odd, even or a range, then press Crop PDF.
Cropping hides content — it does not delete it
This is the single most misunderstood thing about PDF cropping, and it matters. A PDF page carries several rectangles. The MediaBox is the sheet the page was defined on. The CropBox is the window a reader displays. Cropping sets those rectangles smaller; every drawing instruction outside the window is still in the file, just outside the frame.
That is exactly what you want for trimming scanner shadows or the grey gutter of a photocopy. It is exactly what you do not want if the material outside the box is confidential — someone can widen the boxes again and get it back. For that case you need redaction, which rasterises the page and destroys the underlying objects.
| Page box | What it means | Who reads it |
|---|---|---|
| MediaBox | The physical sheet the page is imposed on. Required on every page. | Everything, including old printer RIPs |
| CropBox | The region a viewer shows and a printer images. Defaults to the MediaBox. | Acrobat, Preview, Chrome, most print drivers |
| BleedBox / TrimBox / ArtBox | Prepress hints for finished size and bleed. Ignored on screen. | Commercial print workflows |
The Shrink the MediaBox too switch is on by default because a CropBox-only crop looks perfect in Acrobat and then prints full-size on a device that only reads the MediaBox. Turn it off when you want the original sheet size to stay recorded.
Why one crop works on pages of different sizes
The rectangle you draw is stored as a proportion of the page — 6% in from the left, 4% down from the top — not as a fixed measurement. When it is applied, each page is measured and the proportion is converted into that page’s own points. A report that mixes A4 body pages with A3 fold-out tables therefore gets a visually consistent trim rather than a fixed 20 mm that swallows the small pages and barely touches the large ones.
Rotated pages are handled the same way. If a page carries a 90° rotation flag, the rectangle you drew on screen is mapped back through that rotation before the boxes are written, so the crop lands where you saw it rather than on its side.
Common reasons to crop
- Reading on a small screen. Trimming a 25 mm margin off each side of an academic paper makes the text roughly 15% larger on a tablet without any zooming.
- Scanner artefacts. A flatbed scan of a smaller original leaves a black or grey border. Auto-detect finds the paper edge and removes it in one step.
- Slide decks. Exported slides often sit inside a large canvas. Cropping to the slide area makes them fill the screen in a PDF reader.
- Removing a header or footer band. Trim from the top or bottom only; the content is hidden from the printed output even though the text layer is still searchable.
Nothing is uploaded
The page preview is rendered by pdf.js in a web worker inside this tab, and the crop itself is written by pdf-lib in the same tab. There is no server in this product that could receive the file. Load the page, switch off your network, and the tool still works — which is the only proof of a privacy claim that is worth anything.
Questions
Does cropping delete the content outside the box?
No. Cropping changes the visible page box, so readers and printers show only the area you kept — but the original objects are still inside the file and can be recovered by re-cropping. If you need content genuinely removed, rasterise or redact the page instead.
What is the difference between the CropBox and the MediaBox?
The MediaBox is the physical sheet the page is defined on; the CropBox is the region a viewer displays. Most software honours the CropBox, but some printers and older tools only read the MediaBox. This tool sets both by default, which is why the crop looks right everywhere.
Can I crop every page at once when the pages are different sizes?
Yes. The crop is stored as a proportion of each page rather than as fixed millimetres, so a mixed A4-and-A3 document is trimmed by the same relative amount on every page.
How does auto-detect margins work?
The previewed page is rendered at low resolution in your browser, every pixel is scanned for the bounding box of non-white content, and 2 mm of breathing room is added so descenders and rules are not clipped.
Will the text still be searchable afterwards?
Yes. Nothing is converted to an image — only the page boxes change — so text, fonts, vectors, links and bookmarks all survive exactly as they were.