Reference tables
QR code size by scanning distance
Printed width should be at least the scanning distance divided by ten. This table applies that rule across the distances that occur in practice, from a business card at 25 cm to large-format signage at 30 m.
The table
| Scanning distance | Minimum code width |
|---|---|
| 10 cm | 1.0 cm |
| 20 cm | 2.0 cm |
| 25 cm | 2.5 cm |
| 30 cm | 3.0 cm |
| 40 cm | 4.0 cm |
| 50 cm | 5.0 cm |
| 75 cm | 7.5 cm |
| 100 cm | 10.0 cm |
| 150 cm | 15.0 cm |
| 200 cm | 20.0 cm |
| 300 cm | 30.0 cm |
| 500 cm | 50.0 cm |
| 1000 cm | 100.0 cm |
| 2000 cm | 200.0 cm |
| 3000 cm | 300.0 cm |
That is the code, excluding the four-module quiet zone, the frame and any caption.
Where each distance occurs
| Distance | Context |
|---|---|
| 20–30 cm | Business card, flyer, invitation, book page |
| 30–40 cm | Restaurant table tent, invoice, desk card |
| 40–60 cm | Shop counter, shelf-edge label, product label |
| 1 m | Corridor poster, lift lobby, door sign |
| 2 m | Wall poster at eye level, shop window from the pavement |
| 3 m | Sign across a lobby, exhibition panel |
| 5–10 m | Large indoor signage, stadium concourse |
| 10 m+ | Out-of-home. Usually impractical — see below |
The rule assumes a moderate payload
It is a proxy for angular size, calibrated for a typical phone camera and a code of around 30–45 modules. A denser code needs more than the rule suggests.
The complete check is:
module size = printed width ÷ module count ≥ the floor for your medium
| Medium | Minimum module |
|---|---|
| Offset, coated stock | 0.4 mm |
| Uncoated stock | 0.5 mm |
| Thermal transfer, 203 dpi | 0.5 mm |
| Thermal transfer, 300 dpi | 0.34 mm |
| Laser-marked metal | 0.5 mm |
| Screen print on fabric | 1.0 mm |
| Laser-engraved wood | 1.0 mm |
| 3D print | 1.5 mm |
| Embroidery | 2.0 mm |
Beyond about 5 metres
The arithmetic stops being the constraint and the situation does. Nobody scans a code they cannot approach, and nobody scans while moving. A 3 m code on a roadside billboard is both impractical to print and useless to a driver.
Out-of-home QR codes work where the audience is stationary: bus shelters, platform posters, lift lobbies, queue barriers. There the distance drops to 1–3 m and the rule becomes easy to satisfy.
FAQ
How far away can a QR code be scanned?
Roughly ten times its printed width, with a typical phone camera and a moderate payload. A 10 cm code is readable from about a metre.
What size QR code do I need for a poster?
Ten to thirty centimetres, depending on whether it is read from one metre or three. Most posters carry codes far smaller than this.
Does the quiet zone count toward the width?
No. The rule applies to the code itself; the four-module quiet zone is additional clear space around it.
Why do billboard QR codes not work?
A 30 m viewing distance requires a 3 m code, and drivers cannot scan while moving. Out-of-home codes only work where the audience is stationary.