To gauge which ring size is suitable for you, refer to below instruction on how to measure. Take note that your ring size can differ by 1mm - 0.5mm with the difference in season. During Winter, our fingers will usually contract as compared to Summer due to the difference in Temperature.  
   
     
 
Ring Size Diameter (mm) Length (mm) Ring Size Diameter (mm) Length (mm)
size 1 13.1 44 size 11 16.4 54
size 2 13.6 45 size 12 16.6 55
size 3 13.8 46 size 13 17.0 56
size 4 14.2 47 size 14 17.2 57
size 5 14.5 48 size 15 17.7 58
size 6 14.7 49 size 16 18.0 59
size 7 15.0 50 size 17 18.3 60
size 8 15.4 51 size 18 18.6 61
size 9 15.8 52 size 19 19.0 62
size 10 16.0 53 size 20 19.3 63