Printing a QR code too small for its intended scanning distance is one of the most common — and most avoidable — reasons a code fails in the field. These are practical starting points, not hard physics.
Minimum sizes by use case
| Use case | Min size | Typical scanning distance |
|---|---|---|
| Business card | 2 cm × 2 cm | 5–15 cm |
| Flyer / brochure | 3 cm × 3 cm | 10–30 cm |
| Poster (A3/A2) | 4–5 cm × 4–5 cm | 30–60 cm |
| Retail shelf label | 2.5 cm × 2.5 cm | 10–20 cm |
| Outdoor billboard | 20 cm × 20 cm+ | 3–10 m |
| Screen / digital display | roughly 100 px × 100 px minimum | arm's length |
A rule of thumb: roughly 1:10
A rough guideline used across the print industry: the maximum reliable scanning distance is about ten times the width of the code. A 3 cm code tends to hold up to roughly 30 cm away; a 10 cm code to roughly a metre. Treat this as a starting estimate to size against, not a guarantee — actual results shift with lighting, camera quality, and the angle someone's holding their phone at.
What pushes the minimum size up
- Data density — more encoded content means more modules packed in, which needs more physical space to stay legible at the same distance
- Error correction level — higher levels (see the error correction guide) add modules, which is the trade-off for their extra resilience
- A logo — takes up centre space that would otherwise hold data, effectively shrinking the working scan area
- Print method — offset printing renders sharper module edges than a cheap inkjet run; screens are typically crisp at any reasonable size, since there's no ink to bleed
Print a physical proof and scan it — with the actual printer and material you'll use — before committing to a full run. Lighting, viewing angle, and surface finish all affect real-world scan reliability in ways a screen preview simply can't show you, and the 1:10 rule is only ever a starting point.