# When not to use a QR code

> Do not use a QR code where the audience is moving, where a tappable link already exists, where it would be the only route to essential information, or where the code cannot be printed at least a tenth of the viewing distance. In those cases it is decoration at best.

Source: https://useqr.app/docs/basics/when-not-to-use-a-qr-code · Last reviewed 2026-08-21 · UseQR is free forever, MIT licensed, no signup.

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## The four disqualifying conditions

**1. The audience is moving.** A driver at 50 km/h covers 14 m per second. There is no
sequence of events in which a passenger unlocks a phone, opens the camera and frames a
billboard code. The same applies to escalators, station concourses at rush hour, and
anything on a vehicle in motion.

**2. The user is already on a device.** A QR code on a web page, in an email, or in a PDF
read on a laptop asks someone to pick up a second device to do what a link would do in one
tap. Show a link; show a code only when a second device is genuinely likely.

**3. It would be the only route.** Allergen information, safety instructions, statutory
notices, benefit applications, aftercare guidance. Anyone without a smartphone, without
data, with low vision, or with a flat battery is excluded. In several jurisdictions that is
a legal exposure, not just poor service.

**4. There is not enough physical room.** Printed width must be at least the viewing
distance divided by ten. If a shelf-edge strip gives you 1 cm and the payload needs 2 cm,
the answer is a shorter payload or no code — not a smaller code.

## The cases people get wrong most often

- **Business cards** where the code is 1 cm and encodes a full vCard. The modules end up
  below what a press can print.
- **Billboards.** See above.
- **Codes on a website** "so people can share it to their phone" — a share sheet does this
  better.
- **Codes with no reason attached.** A bare code in the corner of a poster gets ignored.
- **Codes pointing at a homepage.** The scanner has to search for what you meant.
- **Foil, embossed and dark-on-dark codes** that look beautiful and do not scan.

## The test

Before printing, answer these:

1. Will the reader be **standing still** for at least ten seconds?
2. Is there a **stated reason** to scan, in words, next to the code?
3. Is the code at least **viewing distance ÷ 10** wide?
4. Does the destination work **on a phone, on cellular, in one second**?
5. Is there a **non-QR alternative** for people who cannot use it?

Two or more "no" answers means the code is decoration.

## FAQ

### Do QR codes work on billboards?
Effectively no. The ten-to-one rule means a 30 m viewing distance needs a 3 m code, and drivers cannot scan while moving. Use out-of-home codes only where the audience is stationary, such as bus shelters and lift lobbies.

### Should I put a QR code on my website?
Only if a second device is genuinely likely — for example, a code to open a page on a phone from a desktop. Otherwise a link does the same job in one tap.

### Can a QR code replace printed safety information?
No. Anyone without a smartphone, data, or usable vision is excluded, and in many jurisdictions that is a legal problem as well as a practical one.

### What size is too small?
Anything below the viewing distance divided by ten. If the available space is smaller than that, shorten the payload so the code has fewer modules — do not just shrink the code.

## Try it

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