The 1:10 rule
A phone has to tell the individual squares of a code apart. The further away it is, the bigger they need to be. In practice a simple rule works: the code should be at least a tenth of the scanning distance wide. You hold a business card about 30 cm from your eyes, so 3 cm is enough. A poster on a wall is seen from 1.5 metres, so the code needs at least 15 cm.
That's for a normal code with a short link. When the code holds a long address or a contact with every detail, it has more squares and needs even more room. Try it:
What the code contains
Minimum code width
5 cm
about the size of a bank card
Rule: width ≥ a tenth of the distance; denser codes need more.
The margin around the code isn't decoration
A QR code needs an empty light border around it, called the quiet zone. The recommended width is four of the code's squares. Designers love trimming it so the code sits tight against text or the edge of a flyer, and then the phone can't tell where the code begins. If the code looks glued to other elements, give it some space.
Which file to send to the printer
- SVG or PDF for professional print. They're vectors, so the code stays sharp at any size, even on a billboard.
- PNG is fine for home printing and the web. For print, plan on 300 dots per inch: a 5 cm code needs an image of at least 600 × 600 px.
- Never enlarge a small PNG from your phone. The square edges blur and the code becomes unreliable.
Contrast and colour
Size won't help if the phone can't see the difference between code and background. A dark code on a light background always works. Most modern phones read a light code on a dark background, but older scanners don't. Avoid pastel colours on white paper, and gold or silver foil that glints in the light.
Quick size guide
- Business card: 2.5 to 3 cm
- A5 flyer or handheld menu: 3 to 4 cm
- Table stand: 5 cm
- A3 poster on a wall: 10 to 15 cm
- Shop window or roll-up banner: 20 to 30 cm
- A poster seen from across the street: 40 cm or more
Questions people ask
What's the smallest QR code you can print?⌄
In practice about 2 cm with a short link and good print quality. A smaller code sometimes works, but only up close and not on every phone.
Can a QR code be too big?⌄
Hardly. The only problem is when people can't step far enough back to fit the whole code in the frame, like a giant code in a narrow corridor.
Does a logo in the middle help or hurt?⌄
A logo covers space the code has to make up for with error correction. A logo up to a quarter of the code's width is fine; the generator raises correction automatically.
Why is a dynamic code smaller?⌄
It only holds a short link, so it has fewer squares. At the same size the squares are bigger and the phone reads them from further away.
Create a print-ready QR code
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