# QR codes in out-of-home advertising

> Placement physics decides everything — a scan needs a stopped viewer within reach and a code at least one tenth of the viewing distance wide. Street furniture and transit interiors, at 1 to 3 metres with 30 seconds or more of dwell, work well. A roadside billboard at 50 metres and 2 seconds never will.

Source: https://useqr.app/docs/marketing/qr-codes-in-out-of-home-advertising · Last reviewed 2026-08-21 · UseQR is free forever, MIT licensed, no signup.

---

## Two physical constraints decide everything

Scanning requires a person who is **stopped, with a free hand, within camera range**, looking at a code **at least one tenth of the viewing distance wide** — the [10:1 rule](/docs/print/the-10-to-1-distance-rule). Every OOH format either satisfies both constraints or it does not, and no creative brilliance rescues a format that fails the physics. Evaluate any placement with two questions: *how far away is the viewer* and *how long are they stationary*.

## The placement table

| Placement | Distance | Dwell | Code width needed | Verdict |
|---|---|---|---|---|
| Transit interior panels (bus, metro) | 1–2 m | minutes | **10–20 cm** | best in OOH — captive, seated, bored |
| Bus shelters, street furniture | 1–3 m | 30 s – minutes | **10–30 cm** | excellent |
| Station platform posters | 3–10 m | 1–5 min | **30 cm – 1 m** | works when the code is genuinely huge |
| Pedestrian-zone billboards | 5–15 m | seconds, walking | **0.5–1.5 m** | marginal — few people stop |
| Roadside billboards | 30–100 m | 1–3 s, driving | **3–10 m** | no — and inviting drivers to point phones at signs is its own problem |

The pattern: **value concentrates where people wait.** Transit interiors and shelters combine short distance, long dwell and a phone already in hand. Formats built for glancing reach — the classic billboard — are built for memory, not response; the numbers behind the widths are in the [size-by-distance table](/docs/reference/qr-code-size-by-distance-table) and the [billboard sizing page](/docs/print/qr-code-size-for-a-billboard).

## Making the workable placements work

- **Size for the furthest realistic scanner**, not the average. A shelter poster scanned from the bench and from the kerb should be sized for the kerb; the [size calculator](/size-calculator) does the arithmetic per distance.
- **Put the code at standing eye-to-waist height.** A code at the top of a 2 m panel adds distance and angle for no reason.
- **Give the reason, not the mechanism.** "See tonight's departures", not "Scan for more information" — the [call-to-action page](/docs/marketing/qr-code-call-to-action) is the difference between decoration and response.
- **Add a short typeable URL** under the code. It rescues the too-far viewer, the broken camera, and — on roadside formats — is the *only* honest response mechanism.
- **Tag each site**: one code per location with its own parameter, so the campaign learns which sites respond. Sequencing and comparison method is on [A/B testing QR placement](/docs/marketing/ab-testing-qr-code-placement).

## Set expectations before anyone promises numbers

Even a perfect placement converts a minority of viewers — most people moved by OOH search the brand later rather than scan. Scans are a response floor and a site-comparison tool, not a reach measurement; [what scan rate should you expect](/docs/marketing/what-scan-rate-should-you-expect) covers why any promised percentage should be treated with suspicion. Verify the artwork decodes at final size with the [validator](/validate) before the print deadline — OOH misprints are the most expensive kind.

## FAQ

### Do QR codes work on billboards?
On pedestrian and transit formats, yes — viewers are close and stationary. On roadside billboards, no: a driver at 50 metres passing in two seconds would need a code several metres wide and a stopped car. Use a memorable short URL there instead.

### Where do QR codes work best in out-of-home advertising?
Where people wait: transit interior panels, bus shelters, station platforms, street furniture. These combine one-to-three-metre viewing distance, dwell measured in minutes, and a phone already in the viewer's hand.

### How big should a QR code be on outdoor advertising?
At least one tenth of the furthest expected scanning distance: 10–20 cm for transit interiors, up to a metre for platform posters viewed across tracks. When in doubt, size up — oversize codes cost nothing and rescue marginal scanners.

### What scan rate should an OOH campaign expect?
No trustworthy universal number exists, because impressions of a poster cannot be counted. Compare your own sites against each other with per-location codes, and treat scans as a floor on response rather than a measure of the campaign's total effect.

## Try it

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