Ring Size Chart

All sizes are approximate
U.S. & Canadian Standard	Inside Diameter mm/inches	Inside Circumference mm/inches
1½	12.78 / .503	40.2 / 1.580
2	13.21 / .520	41.5 / 1.634
2½	13.61 / .536	42.7 / 1.684
3	14.04 / .553	44.0 / 1.739
3½	14.45 / .569	45.2 / 1.788
4	14.86 / .585	46.5 / 1.836
4½	15.27 / .601	47.8 / 1.888
5	15.70 / .618	49.0 / 1.941
5½	16.10 / .634	50.2 / 1.992
6	16.51 / .650	51.5 / 2.042
6¼	N/A	N/A
6½	16.92 / .666	52.8 / 2.092
7	17.35 / .683	54.0 / 2.146
7½	17.63 / .699	55.3 / 2.196
8	18.19 / .716	56.6 / 2.249
8½	18.59 / .732	57.8 / 2.300
9	18.99 / .748	59.1 / 2.350
9½	19.41 / .764	60.3 / 2.400
10	19.84 / .781	61.6 / 2.463
10½	20.24 / .797	62.8 / 2.504
11	20.68 / .814	64.1 / 2.567
11½	21.01 / .830	66.0 / 2.608
12	21.41 / .846	67.3 / 2.658