Surface guide
QR codes on wristbands
A wristband QR code has to work on a curved, moving, sweaty surface about 15–20 mm tall. Keep the payload tiny so the code stays low-version, use error correction Q, and consider a rectangular rMQR code if your scanners support it.
| Typical scan distance | 20–30 cm |
|---|---|
| Minimum code width | 2–2.5 cm |
| Error correction | Q |
Height is the binding constraint
A typical wristband gives 15–20 mm of usable height. That caps the code at about 20 mm square, so the payload must be short: an opaque id of 8–12 characters, resolved server-side. A URL with a long path will not fit legibly.
Curvature
A wrist is a tight radius. Keep the code within roughly a third of the visible arc and expect the wearer to have to turn their wrist. Version 2 or above so alignment patterns exist.
Materials
| Type | Life | Notes |
|---|---|---|
| Tyvek | 1–3 days | Cheap, tears deliberately; ink can smudge when wet |
| Vinyl | 1–2 weeks | Sweat and water resistant |
| Silicone | reusable | Needs laser marking or a printed insert |
| Hospital polypropylene | days | Must survive alcohol gel and hand washing |
Alcohol hand gel is the specific killer in clinical settings. It dissolves many inks. Specify a gel-resistant print or a laminated insert.
Consider rMQR
rMQR is rectangular and suits a band far better than a square. Industrial imagers read it; phone cameras generally do not, so only choose it if you control the scanners.