How big should a QR code be for print?

The rule of thumb: distance divided by ten

The minimum size of a QR code is about one tenth of the distance it will be scanned from. A code read from a flyer in the hand, at 20 to 30 centimetres, should be at least 2 to 3 centimetres across. A code on a poster read from a metre away should be 10 centimetres. A code on a shop window read from the pavement, at 2 to 3 metres, needs 20 to 30 centimetres, and a code on a billboard read from 10 metres needs a metre. The ratio is what matters: a bigger code can always be scanned from closer, but a small code cannot be scanned from far away.

Two centimetres by two centimetres is the practical floor for print, whatever the distance. Below that, ordinary printing tolerances and ordinary phone cameras start to disagree, and a code that scans on one phone will fail on another.

Module count changes the answer

A QR code is a grid of small squares called modules, and the number of modules depends on how much text the code holds. A short address makes a code of 25 or 29 modules a side; a long address with tracking parameters can need 45 or more. The phone has to resolve each module, so at the same printed size the denser code has smaller modules and is harder to read. The rule above assumes a code of ordinary density. For a dense code, go bigger.

This is the quiet argument for dynamic codes on anything printed small. A dynamic code holds a short link of a few dozen characters and stays coarse, whatever the length of the destination behind it. The same label can carry a coarse dynamic code or a dense static one, and only the first scans reliably at two centimetres.

Keep the quiet zone

The quiet zone is the empty margin around the code. The standard asks for four modules of clear space on every side, and scanners use it to find the edges of the code. Designers remove it because it looks like wasted space, and that is the single most common reason a correctly sized code fails. Keep the margin in the same colour as the code's background, and keep text, borders and other artwork out of it. A frame with a call to action is fine as long as it sits outside the quiet zone, which is how our generator draws it.

Contrast and surface

• Dark modules on a light background. Any dark colour on any light one works; a light code on a dark background, or a mid-grey code on a pastel, does not scan reliably.
• Matte beats gloss. Glossy laminate and glass reflect the light the phone needs, so a code behind glass should be bigger than the rule says, and placed where the sun does not hit it.
• Flat beats curved. A code wrapped around a bottle or a cable distorts; keep it on a flat area, or make it small enough that the curve across it is negligible.
• Printed, not photocopied. Every generation of copying blurs the module edges. Print from the original file each time.

Which file to give the printer

Give the printer a vector file: SVG. A vector code scales from a business card to a billboard without going soft, and the printer places it directly in the artwork at whatever size the layout needs. A PNG is a grid of pixels; enlarged, its edges blur, and blurred module edges are exactly what a scanner struggles with. PNG is right for screens, e-mail and a quick test print at the size it was made. On QR Solutions the PNG download is on every plan and SVG from Starter.

If you must use a bitmap, export it at the size it will be printed, at 300 dots per inch, and never let the layout software scale it up. And whatever the format, keep error correction at M or higher for print; a logo in the code wants H.

Test it before the print run

Print one copy on an ordinary office printer at the final size, put it where the real one will go, and scan it from the distance a real person will stand at, with more than one phone, in the real light. Thirty seconds of testing catches the size, the quiet zone and the contrast at once, and it is the only test that counts. If the office print scans and the professional print does not, the difference is the surface or the ink, not the code.

Frequently asked questions