Ring Size Conversion Chart

RING SIZE CONVERSION CHART:

INSIDE DIAMETER
(INCHES)
INSIDE DIAMETER
(MM)
INSIDE CIRC. 
(INCHES)
INSIDE CIRC. 
(MM)
NUMERICAL SIZES
(US, CANADA, ASIA)
ALPHABETICAL SIZES
(AUSTRALIA, UK, ETC)
0.458" 11.6 mm 1.438" 36.5 mm 0  
0.466" 11.8 mm 1.463" 37.2 mm 1/4  
0.474" 12 mm 1.488" 37.8 mm 1/2 A
0.482" 12.2 mm 1.513" 38.4 mm 3/4 A 1/2
0.49" 12.4 mm 1.539" 39.1 mm 1 B
0.498" 12.6 mm 1.564" 39.7 mm 1 1/4 B 1/2
0.506" 12.9 mm 1.589" 40.4 mm 1 1/2 C
0.514" 13.1 mm 1.614" 41 mm 1 3/4 C 1/2
0.522" 13.3 mm 1.639" 41.6 mm 2 D
0.53" 13.5 mm 1.664" 42.3 mm 2 1/4 D 1/2
0.538" 13.7 mm 1.689" 42.9 mm 2 1/2 E
0.546" 13.9 mm 1.714" 43.5 mm 2 3/4 E 1/2
0.554" 14.1 mm 1.74" 44.2 mm 3 F
0.562" 14.3 mm 1.765" 44.8 mm 3 1/4 F 1/2
0.57" 14.5 mm 1.79" 45.5 mm 3 1/2 G
0.578" 14.7 mm 1.815" 46.1 mm 3 3/4 G 1/2
0.586" 14.9 mm 1.84" 46.7 mm 4 H
0.594" 15.1 mm 1.865" 47.4 mm 4 1/4 H 1/2
0.602" 15.3 mm 1.89" 48 mm 4 1/2 I
0.61" 15.5 mm 1.915" 48.7 mm 4 3/4 J
0.618" 15.7 mm 1.941" 49.3 mm 5 J 1/2
0.626" 15.9 mm 1.966" 49.9 mm 5 1/4 K
0.634" 16.1 mm 1.991" 50.6 mm 5 1/2 K 1/2
0.642" 16.3 mm 2.016" 51.2 mm 5 3/4 L
0.65" 16.5 mm 2.041" 51.8 mm 6 L 1/2
0.658" 16.7 mm 2.066" 52.5 mm 6 1/4 M
0.666" 16.9 mm 2.091" 53.1 mm 6 1/2 M 1/2
0.674" 17.1 mm 2.116" 53.8 mm 6 3/4 N
0.682" 17.3 mm 2.141" 54.4 mm 7 N 1/2
0.69" 17.5 mm 2.167" 55 mm 7 1/4 O
0.698" 17.7 mm 2.192" 55.7 mm 7 1/2 O 1/2
0.706" 17.9 mm 2.217" 56.3 mm 7 3/4 P
0.714" 18.1 mm 2.242" 56.9 mm 8 P 1/2
0.722" 18.3 mm 2.267" 57.6 mm 8 1/4 Q
0.73" 18.5 mm 2.292" 58.2 mm 8 1/2 Q 1/2
0.738" 18.7 mm 2.317" 58.9 mm 8 3/4 R
0.746" 18.9 mm 2.342" 59.5 mm 9 R 1/2
0.754" 19.2 mm 2.368" 60.1 mm 9 1/4 S
0.762" 19.4 mm 2.393" 60.8 mm 9 1/2 S 1/2
0.77" 19.6 mm 2.418" 61.4 mm 9 3/4 T
0.778" 19.8 mm 2.443" 62.1 mm 10 T 1/2
0.786" 20 mm 2.468" 62.7 mm 10 1/4 U
0.794" 20.2 mm 2.493" 63.3 mm 10 1/2 U 1/2
0.802" 20.4 mm 2.518" 64 mm 10 3/4 V
0.81" 20.6 mm 2.543" 64.6 mm 11 V 1/2
0.818" 20.8 mm 2.569" 65.2 mm 11 1/4 W
0.826" 21 mm 2.594" 65.9 mm 11 1/2 W 1/2
0.834" 21.2 mm 2.619" 66.5 mm 11 3/4 X
0.842" 21.4 mm 2.644" 67.2 mm 12 X 1/2
0.85" 21.6 mm 2.669" 67.8 mm 12 1/4 Y
0.858" 21.8 mm 2.694" 68.4 mm 12 1/2 Z
0.866" 22 mm 2.719" 69.1 mm 12 3/4 Z 1/2
0.874" 22.2 mm 2.744" 69.7 mm 13  
0.882" 22.4 mm 2.769" 70.3 mm 13 1/4 Z1
0.89" 22.6 mm 2.795" 71 mm 13 1/2  
0.898" 22.8 mm 2.82" 71.6 mm 13 3/4 Z2
0.906" 23 mm 2.845" 72.3 mm 14 Z3
0.914" 23.2 mm 2.87" 72.9 mm 14 1/4  
0.922" 23.4 mm 2.895" 73.5 mm 14 1/2 Z4
0.93" 23.6 mm 2.92" 74.2 mm 14 3/4  
0.938" 23.8 mm 2.945" 74.8 mm 15  
0.946" 24 mm 2.97" 75.4 mm 15 1/4  
0.954" 24.2 mm 2.996" 76.1 mm 15 1/2  
0.962" 24.4 mm 3.021" 76.7 mm 15 3/4  
0.97" 24.6 mm 3.046" 77.4 mm 16