About ring size



JP mm

inches US
Canada
UK
Australia
Italy
Switzerland
Germany
  Inner circumference        
#4 43.98 1.735 3 F 4 14
#5 45.03 1.79 3.5 G 5  1/4 14  1/2
#6 46.08          
#7 47.12 1.835 4 H 1/2 7  1/4 15
#8 48.12 1.89 4.5 I 1/2 8  3/4 15  1/4
#9 49.22 1.943 5 J 1/2 9  1/2 15  3/4
#10 50.27          
#11 51.31 2 5.5 L 11  3/4 16
#12 52.36 2.045 6 M 12  3/4 16  1/2
#13 53.41 2.1 6.5 N 14 17
#14 54.45 2.15 7 O 15  1/4 17  1/4
#15 55.50 2.2 7.5 P 16  1/2 17  3/4
#16 56.55 2.25 8 Q 17  3/4 18
#17 57.60 2.3 8.5 Q 1/2 18  1/2 18  1/2
#18 58.64 2.35 8.75 S 19  3/4 19
#19 59.69 2.4 9 T 21 19  1/2
#20 60.74 2.46 9.5 T 1/2 22 20
#21 61.78   9.75      
#22 62.83 2.51 10.25 U 1/2 23  1/4 20  1/4
#23 63.88 2.56 10.75 V 1/2 24 20  3/4
#24 64.93 2.61 11 X 25  3/4 21
#25 65.97 2.63 11.25 Y 27  1/2 21  1/4
#26 67.02 2.71 12 Z 28  3/4 21  3/4
#27 68.07 2.76     29  1/4 22
#28 69.11 2.80 12.75 Z 1/2    
#29 70.16 2.84 13.25 Z1    
#30 71.21 2.88 13.5 Z2    
#31 72.26 2.93 14 Z3    

example) Tell us your closer size in "JP15" or "JP21.5".

Wikipedia World ring gauge is here