Use the chart below to determine the size of your ring

Circumference (mm) Diameter of ring (mm) US Size EU Size AU Size
51.8 16.5 6 52 L 1/2
53.1 16.9 6.5 53 M 1/2
54.4 17.3 7 54 N 1/2
55.7 17.7 7.5 55 O 1/2
56.9 18.1 8 57 P 1/2

 

see detailed ring size guide