The recommended minimum QR code print size is 2 x 2cm (0.8 x 0.8in) for Dynamic codes and 3 x 3cm (1.2 x 1.2in) for Static codes. However, the best sizing option will depend on your printing material and its ideal scanning distance.
The scanning distance is estimated by the scanning distance to QR code size ratio, which is equal to 10:1. If the approximate distance between the user and the targeted QR code is 30cm, the QR code size must be at least 3cm wide.