In order to help users in understanding Ring sizes and parameters used in different countries, we have pulled out this chart to assist you in doing so. The chart includes inner diameter as well as circumference of a ring in inches and millimetres.

The Ring sizes are measured using simple tools such as Ring sizer stick (or Ring Mandrel) and Ring finger sizer as shown in the images below.

images  J.K Diamonds (Naman)4174

 

The size parameters differ country wise as shown in the table below.

 

Conversion chart for ring sizes
Inside diameterInside circumferenceSizes
(in)(mm)(in)(mm)US,
Canada and
Mexico
UK,
Ireland,
Australia and
New Zealand
China,
Japan,
South America
IndiaItaly,
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
0.50612.851.5940.4C0.5
0.51413.061.614111
0.52213.261.6441.72D221.75
0.5313.461.6742.32.25
0.53813.671.6942.9E333
0.54613.871.7243.643.5
0.55414.071.7444.23F44.25
0.56214.271.7744.8554.75
0.5714.481.7945.5G5.5
0.57814.681.8246.1666
0.58614.881.8446.84H76.75
0.59415.091.8747.477.5
0.60215.291.8948I888
0.6115.491.9248.7J98.75
0.61815.71.9449.3599.25
0.62615.91.9750K1010
0.63416.11.9950.61010.5
0.64216.312.0251.2L1111.25
0.6516.512.0451.96111211.75
0.65816.712.0752.5M1212.5
0.66616.922.0953.1131313.25
0.67417.122.1253.8N13.75
0.68217.322.1454.47141414.5
0.6917.532.1755.1O1515
0.69817.732.1955.71515.75
0.70617.932.2256.3P1616.25
0.71418.142.24578161717
0.72218.342.2757.6Q17.5
0.7318.542.2958.3171818.25
0.73818.752.3258.9R1919
0.74618.952.3459.591819.5
0.75419.152.3760.2S2020.25
0.76219.352.3960.8192120.75
0.7719.562.4261.4T21.5
0.77819.762.4462.110202222
0.78619.962.4762.710¼U212322.75
0.79420.172.4963.410½2223.25
0.80220.372.526410¾V2424
0.8120.572.5464.611232524.75
0.81820.782.5765.311¼W25.25
0.82620.982.5965.911½242626
0.83421.182.6266.611¾X26.5
0.84221.392.6567.212252727.25
0.8521.592.6767.812¼Y2827.75
0.85821.792.768.512½Z2628.5
0.866222.7269.112¾2929
0.87422.22.7569.713273029.75
0.88222.42.7770.413¼Z130.5
0.8922.612.87113½3131
0.89822.812.8271.713¾Z23231.75
0.90623.012.8572.314Z332.25
0.91423.222.8772.914¼3333
0.92223.422.973.614½Z433.5
0.9323.622.9274.214¾3434.25
0.93823.832.9574.8153534.75
0.94624.032.9775.515¼35.5
0.95424.23376.115½3636.25
0.96224.433.0276.815¾36.75
0.9724.643.0577.4163737.5

 

Ring sizes can be measured physically by a plastic or metal ring sizer, or by measuring the girth of a ring that already fits. There are also online measuring tools available, though they may not be as precise as checking for the size physically.

The circumference of the ring (inner circle) is the distance around it. It is calculated based on the formula, π × diameter (where π=3.14). For example, the Indian size 10 has a diameter 15.9 mm. Hence the circumference would be 3.14 x 15.9 = Approx. 50 mm.

The average ring size for women in India is around Size 13-14 and for men, it is between Size 16-18.

Source