Surface guide
QR codes on billboards and out-of-home
A billboard QR code must be at least a tenth of the viewing distance — a metre wide at 10 m, five metres at 50 m. For most roadside billboards that is impractical, and the honest answer is usually that a QR code is the wrong tool.
| Typical scan distance | 10–50 m |
|---|---|
| Minimum code width | 1–5 m |
| Error correction | L |
Do the arithmetic before committing
| Viewing distance | Minimum code width |
|---|---|
| 10 m | 1 m |
| 20 m | 2 m |
| 30 m | 3 m |
| 50 m | 5 m |
A 48-sheet billboard is about 6 × 3 m. A compliant code for a 30 m viewing distance occupies half its height.
Motion makes it worse
A driver at 50 km/h covers 14 m per second. There is no realistic scenario in which a passenger unlocks a phone, opens the camera, frames a code and holds it steady. Roadside billboard QR codes do not work, and pretending otherwise wastes the media spend.
Where out-of-home codes do work
Anywhere the audience is stationary: bus shelters, platform posters, lift lobbies, escalator panels, stadium concourses, queue barriers. There, viewing distance drops to 1–3 m and the code becomes both feasible and effective.
If you must
- Error correction L. At this size every module is huge; redundancy is wasted area.
- Keep the payload minimal — a short domain, no UTM string in the code itself.
- Print a memorable short URL alongside, because most people will type it instead.