# QR code size for a billboard

> A billboard code read from 15 m must be about 1.5 m wide; from 50 m, 5 m wide. Most billboard QR codes are printed far smaller and are never scanned. QR earns its keep at pedestrian scale — bus shelters, platforms, street level — not with drivers passing at speed.

Source: https://useqr.app/docs/print/qr-code-size-for-a-billboard · Last reviewed 2026-08-21 · UseQR is free forever, MIT licensed, no signup.

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## The arithmetic nobody wants

Apply [the ten-to-one rule](/docs/print/the-10-to-1-distance-rule) to billboard distances
and the numbers stop being polite:

| Viewer | Distance | Minimum code width |
|---|---|---|
| Pedestrian at the base | 15 m | 1.5 m |
| Across a wide street | 25 m | 2.5 m |
| Roadside, from a car | 50 m | 5 m |

A 5 m code on a standard 48-sheet (6 × 3 m) billboard *is* the billboard. Most codes
actually printed on billboards are 30–60 cm — sized as if the audience stood 3–6 m away,
which nobody does. They are decoration, not function.

## Dwell time makes it worse

Even a correctly sized code has to survive the clock. At 60 km/h a car covers 16.7 m every
second; a billboard with 200 m of clean sightline is visible for about 12 seconds. Waking
a phone, opening the camera, aiming and holding steady takes 5–8 seconds — and in the
final 50 m the viewing angle steepens past the point where modules resolve. That leaves a
window of roughly two or three usable seconds, for a passenger. **The driver should never
be the target of a scan, full stop.**

## Where roadside codes do work

QR in out-of-home advertising succeeds where feet, not wheels, set the distance:

| Placement | Distance | Code width |
|---|---|---|
| Bus shelter panel | 1–2 m | 10–20 cm |
| Rail platform poster | 2–3 m | 20–30 cm |
| Street-level hoarding | 3–5 m | 30–50 cm |
| Billboard above a pedestrian crossing wait | 15 m | 1.5 m |

The pattern: places where people are stationary for 30 seconds or more with the code
inside comfortable reach of the camera. The broader playbook is in
[QR codes in out-of-home advertising](/docs/marketing/qr-codes-in-out-of-home-advertising),
and the substrate details live on the [billboards surface page](/qr-codes-on/billboards).

## If you must put one on a billboard

- **Shortest possible payload.** A 25-character URL is a version 2 code; at 2.5 m wide,
  each module is a resilient 10 cm.
- **EC L or M**, not H — at distance, module size beats redundancy every time.
- **Print a short, memorable URL beside the code.** For the driver demographic the URL is
  the working channel; a
  [short URL fallback](/docs/design/qr-code-next-to-a-short-url-fallback) means the
  billboard still converts when the code cannot.
- Aim the code at the pedestrian sightline if the site has one — base of the structure,
  crossing waits, car parks.

Check your own numbers with the [size calculator](/size-calculator) before signing the
artwork off, and [confirm the file decodes](/validate) — a code this public is an
expensive place to discover an encoding mistake.

## FAQ

### How big does a QR code need to be on a billboard?
One tenth of the viewing distance — about 1.5 m wide for viewers 15 m away and 5 m wide at 50 m. If the code cannot be that large, it will function as decoration rather than as a scannable link.

### Can drivers scan QR codes on billboards?
They should not, and mostly cannot. At 60 km/h the usable window after unlocking and aiming a phone is a couple of seconds, and the approach angle destroys readability near the end. Design for passengers, pedestrians, or a memorable short URL instead.

### Do QR codes on billboards ever work?
At pedestrian scale, yes — bus shelters, platform posters and street-level sites where people stand still within a few metres. Classic elevated roadside billboards are the weakest possible QR placement.

### What should a billboard QR code link to?
The shortest stable URL you control. Short payloads keep the code at a low version, which makes each module larger and the code scannable from further away — the entire game at billboard distances.

## Try it

- https://useqr.app/url
- https://useqr.app/size-calculator
- https://useqr.app/validate