Ring Size Chart

Ring Size Chart

Inside diameterInside circumferenceSizes
(in)(mm)(in)(mm)United States,
Canada and
Mexico
United Kingdom,
Australia and
New Zealand
South AmericaIndiaItaly,
Spain,
Netherlands,
Switzerland
0.45811.631.4436.50    
0.46611.841.4637.2¼    
0.47412.041.4937.8½A   
0.48212.241.5138.5¾   
0.4912.451.5439.11B1  
0.49812.651.5639.7   
0.50612.851.5940.4C  0.5
0.51413.061.6141 11
0.52213.261.6441.72D221.75
0.5313.461.6742.3  2.25
0.53813.671.6942.9E333
0.54613.871.7243.6 43.5
0.55414.071.7444.23F4 4.25
0.56214.271.7744.8554.75
0.5714.481.7945.5G  5.5
0.57814.681.8246.1666
0.58614.881.8446.84H7 6.75
0.59415.091.8747.4 77.5
0.60215.291.8948I888
0.6115.491.9248.7J 98.75
0.61815.71.9449.359 9.25
0.62615.91.9750K 1010
0.63416.11.9950.610 10.5
0.64216.312.0251.2L 1111.25
0.6516.512.0451.96111211.75
0.65816.712.0752.5M12 12.5
0.66616.922.0953.1131313.25
0.67417.122.1253.8N  13.75
0.68217.322.1454.47141414.5
0.6917.532.1755.1O 1515
0.69817.732.1955.715 15.75
0.70617.932.2256.3P 1616.25
0.71418.142.24578161717
0.72218.342.2757.6Q  17.5
0.7318.542.2958.3171818.25
0.73818.752.3258.9R 1919
0.74618.952.3459.5918 19.5
0.75419.152.3760.2S 2020.25
0.76219.352.3960.8192120.75
0.7719.562.4261.4T  21.5
0.77819.762.4462.110202222
0.78619.962.4762.710¼U212322.75
0.79420.172.4963.410½22 23.25
0.80220.372.526410¾V 2424
0.8120.572.5464.611232524.75
0.81820.782.5765.311¼W  25.25
0.82620.982.5965.911½242626
0.83421.182.6266.611¾X  26.5
0.84221.392.6567.212252727.25
0.8521.592.6767.812¼Y 2827.75
0.85821.792.768.512½Z26 28.5
0.866222.7269.112¾ 2929
0.87422.22.7569.713 273029.75
0.88222.42.7770.413¼Z1  30.5
0.8922.612.87113½  3131
0.89822.812.8271.713¾Z2 3231.75
0.90623.012.8572.314Z3  32.25
0.91423.222.8772.914¼  3333
0.92223.422.973.614½Z4  33.5
0.9323.622.9274.214¾  3434.25
0.93823.832.9574.815  3534.75
0.94624.032.9775.515¼   35.5
0.95424.23376.115½  3636.25
0.96224.433.0276.815¾   36.75
0.9724.643.0577.416  3737.5

Sourced from Wikipedia