This app works on mobile devices only. Scan the QR code to access it.

Attach a part of any card here, then adjust the size using the slider so that only the black frame is visible Important! The card is for calibration only; no card data is read/used.

Place your ring on the screen and adjust the circle size to match it with the line tracing the inner surface of the ring.

Check Your size is ...

INTERNAL DIAMETER OF THE RING (mm) 15.3 15.7 16.1 16.5 16.9 17.4 17.8 18.2 18.5 18.9 19.4 19.8 20.2 20,68 21,08 21,49 21,89 22,33
USA 5 6 7 8 9 10 10½ 11,00 11½ 12 12½ 13,00