Ring Size Conversion Chart

 Diameter(mm) US & Canada Europe UK & Australia Japan & Singapore
14.1 3 44 F 1/2 4
14.3 45 G 5
14.5 3.5 G 1/2
14.7 46 H 6
14.9 4 47 H 1/2 7
15.1 I
15.3 4.5 48 I 1/2 8
15.5 J
15.7 5 49 J 1/2 9
15.9 50 K
16.1 5.5 K 1/2 10
16.3 51 L
16.5 6 52 L 1/2 11
16.7 M 12
16.9 6.5 53 M 1/2 13
17.1 N
17.3 7 54 N 1/2 14
17.5 55 O
17.7 7.5 O 1/2 15
17.9 56 P
18.1 8 57 P 1/2 16
18.3 Q
18.5 8.5 58 Q 1/2 17
18.8 59 R
19.0 9 R 1/2 18
19.2 60 S
19.4 9.5 61 S 1/2 19
19.6 T
19.8 10 62 T 1/2 20
20.0 U 21
20.2 10.5 63 U 1/2 22
20.4 64 V
20.6 11 V 1/2 23
20.8 65 W
21.0 11.5 66 W 1/2 24
21.2 X
21.4 12 67 X 1/2 25
21.6 Y
21.8 12.5 68 Z 26
22.0 69 Z 1/2
22.2 13 70 27
22.4 Z+1
22.6 13.5 Z+2