Print & production
What size should a QR code be?
Printed width should be at least the scanning distance divided by ten. A code read from 30 cm needs 3 cm; from 2 m, 20 cm; from 10 m, 1 m. If there is not enough room, shorten the payload so the code has fewer, larger modules rather than shrinking the code.
The ten-to-one rule
minimum printed width = scanning distance ÷ 10
| Where it is | Distance | Minimum code width |
|---|---|---|
| Business card, in the hand | 25 cm | 2.5 cm |
| Restaurant table tent | 35 cm | 3.5 cm |
| Product label on a shelf | 50 cm | 5 cm |
| Poster in a corridor | 1 m | 10 cm |
| Wall poster, eye level | 2 m | 20 cm |
| Sign across a lobby | 3 m | 30 cm |
| Large format signage | 10 m | 1 m |
That is the code, excluding the frame, caption and quiet zone.
Why the rule works
It is a proxy for angular size. A phone camera needs roughly 2–3 pixels per module to threshold reliably. Dividing distance by ten produces a code whose modules subtend enough angle for a typical phone camera, with margin for imperfect focus and lighting.
It assumes a moderate payload. A very dense code needs more than the rule suggests, which is why payload length and size must be decided together.
The module floor
The rule's real constraint is module size:
| Condition | Minimum module |
|---|---|
| Offset print on coated stock | 0.4 mm |
| Uncoated stock (ink spread) | 0.5 mm |
| Thermal transfer at 203 dpi | 0.5 mm |
| Thermal transfer at 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 |
Divide your available width by the module count to check.
Worked example
A URL of 45 characters at error correction M is version 3 — 29 modules, plus 4 modules of quiet zone on each side = 37 module widths total.
On a table tent at 35 cm, the rule wants a 3.5 cm code. 35 mm ÷ 29 = 1.2 mm per module — comfortably above every floor above. Good.
Add 100 characters of UTM parameters and it becomes version 6 (41 modules): 35 mm ÷ 41 = 0.85 mm. Still fine, but you have spent margin for nothing.
Put the same code on a shelf-edge label at 15 mm: 15 ÷ 41 = 0.37 mm, below the thermal floor. Now you must shorten the payload.
Do the arithmetic, do not eyeball it
Our size calculator takes the payload, the distance and the medium and returns the number. It is faster than arguing about it in a design review.
FAQ
What is the minimum size for a QR code?
There is no universal minimum — it depends on the module count. As a rule, printed width must be at least the scanning distance divided by ten, and each module must be at least 0.4 mm for offset printing.
How big should a QR code be on 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, which is why they go unscanned.
Can I make a QR code smaller than the rule suggests?
Only by shortening what it encodes. Fewer characters means a lower version, fewer modules, and larger modules at the same overall width.
Does the quiet zone count toward the size?
No. The ten-to-one rule applies to the code itself; the four-module quiet zone is additional clear space around it.