What size should a QR code be to 3D print it
Two simple calculations: one for the nozzle, one for the reading distance. The larger one wins.
2026-09-01 · 6 min read
The size of a printed QR code isn't an aesthetic choice: it's the result of two independent physical constraints. Calculate both and pick the larger one.
Constraint 1: the nozzle
Each module needs at least 1.5 mm a side with a 0.4 mm nozzle (2 mm with a 0.6 mm one). So:
minimum code side = number of modules × 1.5 mm
| Link length | Approx. modules | Minimum side |
|---|---|---|
| Up to 25 characters | 25 x 25 | 38 mm |
| Up to 45 characters | 29 x 29 | 44 mm |
| Up to 80 characters | 33 x 33 | 50 mm |
| Up to 150 characters | 41 x 41 | 62 mm |
| Up to 250 characters | 49 x 49 | 74 mm |
These are rough figures with M-level error correction. With H level (needed if you add a logo), add about four more modules.
Constraint 2: reading distance
The 1-to-10 rule: the code's side should be a tenth of the distance. To scan from 1 meter, 10 cm of code.
How they combine
Example: you want a WiFi plaque readable from 80 cm. Distance calls for an 8 cm code. Your WiFi text generates 33 modules, which need a 5 cm minimum. Distance wins: an 8 cm code, plus margin, gives a plaque of about 100 mm.
Another example: a 45 mm keychain. Its code area measures about 34 mm. With 33 modules you'd get 1.03 mm modules: not good enough. You'd need to shorten the link down to 22-25 modules, or make the keychain bigger.
The margin (quiet zone)
The standard calls for 4 modules of clear margin around the code. In practice, 2 modules is enough for almost every modern reader and saves space, but below that, failures increase sharply. That margin must be clear: no text, no decorative borders, no color changes.
Try it now
Generate your code and its 3D object in under a minute, no sign-up required.
Open the 3D QR generator