QR code size for print
The distance decides the size. Everything else is a consequence of that.
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There is one rule worth memorising and a handful of numbers worth looking up. The rule is that a code should be about a tenth as wide as the distance it will be scanned from, because a camera needs enough pixels across the pattern to resolve the individual modules. Everything below is that rule applied to the surfaces people actually print on.
Getting it wrong is expensive in a specific way: the design looks correct on screen, the proof looks correct in hand, and the failure only appears once the thing is installed and someone tries to scan it from where they naturally stand. A van at three metres and a shelf label at thirty centimetres are the same design problem with a tenfold difference in answer.
The second half of this page covers what a print shop needs from you — resolution, file format and the margin that must stay empty — because a correctly sized code can still fail if it arrives as a small bitmap enlarged to fit.
The rule, and what it means in centimetres
Divide the scanning distance by ten. That is the minimum width of the printed square, edge to edge, not counting the surrounding margin. Add a margin of comfort outdoors, where light and angle are worse than in a shop.
These are minimums for a code of ordinary complexity — a short link of the kind a dynamic code uses. A long URL packed directly into a static code needs more modules in the same space, so scale up.
- Business card, held at 20 cm — 2 cm minimum, 2.5 cm comfortable
- Menu or table tent at 30 cm — 3 cm
- Product packaging at 30 cm — 3 cm, more if the surface curves
- Shelf edge label at 50 cm — 5 cm
- Poster at 1.5 m — 15 cm
- Trade-show banner at 3 m — 30 cm
- Vehicle livery at 5 m — 50 cm
- Building signage at 10 m — 1 m
Resolution: why 300 dpi and what that means in pixels
Print resolution is measured in dots per inch, and 300 dpi is the standard for anything read close up. To find the pixel width you need, take the printed width in inches and multiply by 300 — a 3 cm code is about 1.2 inches, so roughly 350 pixels, and a 30 cm banner code is nearly 3 500.
This is why a downloaded 512-pixel image is fine for a menu and useless for a banner. Enlarging a bitmap does not add detail; it spreads the same pixels over more paper, and the soft stair-stepped edges that result are exactly what makes a decoder hesitate at the size where it is already working hardest.
- 512 px — screens and small labels up to about 4 cm
- 1024 px — most print up to A5
- 2048 px — posters and packaging
- 4096 px — banners, vehicle wraps and signage
Vector removes the arithmetic entirely
An SVG or PDF stores the modules as shapes rather than pixels, so it is sharp at any size from the same file. If the final size is not yet decided, or the same code will appear on a card and a poster, send vector and stop thinking about resolution.
Print shops prefer it for the same reason. A PDF placed at 40 cm and a PDF placed at 4 cm are both correct, and neither needs a conversation about whether the file is big enough.
The margin that has to stay empty
Four modules of blank space on every side. For a 3 cm code of typical complexity that is roughly 4 mm, and it is not a design suggestion — a decoder uses that space to find the code's boundary.
Budget for it in the layout from the start. Discovering it after the artwork is approved means either shrinking the code, which may take it under the minimum for the distance, or reopening a layout everyone has signed off.
Material changes the answer
Matte beats gloss, consistently and by a wide margin. A glossy or laminated surface reflects the light source straight back into the lens, and the highlight lands where the camera is trying to read. If the finish is fixed and glossy, size up.
Curved surfaces cost accuracy. Past about fifteen degrees of curve the modules distort, so a code on a bottle or a cup wants to be flatter or larger than the table suggests. Fabric and corrugated card absorb ink and blur module edges — add ten to twenty per cent.
Questions people ask
What is the smallest QR code that reliably scans?
About 2 cm across for a short link at typical phone-holding distance, with a clean margin and good contrast. Below that you are relying on a modern camera and a steady hand. If the code must be smaller, shorten what it encodes — fewer characters means fewer modules, and each one stays larger.
Does a longer URL need a bigger code?
Yes, and this catches people out. More characters means more modules in the same square, so each module is smaller and needs a closer or better camera. A dynamic code sidesteps it: the printed square holds a short link regardless of how long the real destination is.
What resolution should I send to a printer?
Vector — PDF or SVG — whenever you can, because it is correct at every size. If it has to be a bitmap, work out the final printed width in inches and multiply by 300 to get the pixel width, then generate at that size or the next size up.
Can I scale a QR code up in design software?
A vector file, yes, without limit. A bitmap, no — scaling it up spreads the existing pixels and softens the module edges, which is the failure that shows up at exactly the distance the code was enlarged for.
Does the code have to be square?
Yes. Stretching it in one direction changes the module proportions and most decoders reject the result. If a layout needs a different shape, change the space around the code rather than the code.
Related generators
Need to change it after printing?
That is a dynamic code — and ours keeps redirecting even if you cancel.