Minimum Size

QR code minimum size depends on module identifiability by camera. For smartphone scanning at 10-15cm distance, minimum 2cm × 2cm is recommended. Size varies with QR version (module count) - higher versions encoding more data need larger physical sizes.

Distance-size ratio: QR code size × 10 ≈ maximum scan distance. Recommended sizes by use: business cards (2-3cm), flyers (3-5cm), posters (5-10cm), signs (10cm+), banners (20cm+). Each leaves headroom above the 10:1 floor - a card read at 15cm only requires 15mm - so you are not designing at the limit. Minimizing stored data (shorter URLs, lower error correction, numeric mode) reduces version and enables smaller sizes.