Ring Size Conversion Chart

 

Inside Diameter Inside Circumference Sizes
mm Inches mm Inches UK & Australia US & Canada France & Russia Germany Japan Swiss
14.86 0.585 46.68 1.84 H 1/2 4 - 15 7 -
15.04 0.592 47.25 1.86 I 4 1/4 47 3/4 - - 7 3/4
15.27 0.601 47.97 1.89 I 1/2 4 1/2 - 15 1/4 8 -
15.40 0.606 48.38 1.90 J 4 5/8 49 15 1/2 - 9
15.53 0.611 48.79 1.92 J 1/4 4 3/4 - - - -
15.70 0.618 49.32 1.94 J 1/2 5 - 15 3/4 9 -
15.80 0.622 49.64 1.95 K 5 1/8 50 - - 10
15.90 0.626 49.95 1.97 K 1/4 5 1/4 - - - -
16.00 0.630 50.27 1.98 K 1/2 5 3/8 - - 10 -
16.10 0.634 50.58 1.99 L 5 1/2 51 3/4 16 - 11 3/4
16.30 0.642 51.21 2.02 L 1/4 5 3/4 - - - -
16.41 0.646 51.55 2.03 L 1/2 5 7/8 - - - -
16.51 0.650 51.87 2.04 M 6 52 3/4 16 1/2 12 12 3/4
16.71 0.658 52.50 2.07 M 1/2 6 1/4 - - - -
16.92 0.666 53.16 2.09 N 6 1/2 54 17 13 14
17.13 0.674 53.82 2.12 N 1/2 6 3/4 - - - -
17.35 0.683 54.51 2.15 O 7 55 1/4 17 1/4 14 15 1/4
17.45 0.687 54.82 2.16 O 1/2 7 1/4 - - - -
17.75 0.699 55.76 2.20 P 7 1/2 56 1/2 17 3/4 15 16 1/2
17.97 0.707 56.45 2.22 P 1/2 7 3/4 - - - -
18.19 0.716 57.15 2.25 Q 8 57 3/4 18 16 17 3/4
18.35 0.722 57.65 2.27 Q 1/2 8 1/4 - - - -
18.53 0.729 58.21 2.29 Q 3/4 8 1/2 - 18 1/2 17 -
18.61 0.733 58.47 2.30 R 8 5/8 59 - - 19
18.69 0.736 58.72 2.31 R 1/4 8 3/4 - - - -
18.80 0.740 59.06 2.32 R 1/2 8 7/8 - - - -
18.89 0.748 59.34 2.35 R 3/4 9 - 19 18 -
19.10 0.752 60.00 2.36 S 9 1/8 60 1/4 - - 20 1/4
19.22 0.757 60.38 2.38 S 1/4 9 1/4 - - - -
19.31 0.760 60.66 2.39 S 1/2 9 3/8 - - - -
19.41 0.764 60.98 2.40 S 3/4 9 1/2 - 19 1/2 19 -
19.51 0.768 61.29 2.41 T 9 5/8 61 1/2 - - 21 1/2
19.62 0.772 61.64 2.43 T 1/4 9 3/4 - - - -