Official international ring size conversion

by | Jul 13, 2020


It is important to establish your correct ring size, and this varies from one finger to the next, and between hands. Usually, the hand you write with will have larger ring sizes. What is considered comfortable is very personal- some people prefer a snug fit, others quite loose. There is no right answer provided that the ring is secure.

Ring sizes are expressed differently by region, which can create uncertainty when travelling or purchasing jewellery abroad.

The US and the UK have adopted alpha numeric sizing systems, which are susceptible to minor variations as there are often slight differences from one ring gauge/stick to the next.

The internal circumference measurement is absolute and unambiguous. For example, a size 52 indicates that the inside circumference of the ring is 52mm.

There are two ways to measure ring size: leading edge and middle size. This needs to be specified when quoting your ring size.

Try to avoid measuring your ring size if you are hot (your fingers will be swollen and the measurement will be too big) or too cold (they will measure up too small).

Be aware that if the ring has a wider band width, it will require a larger ring size than usual to comfortably slide over the knuckle of the finger.

Ideally, visit your jeweller for an accurate size fitting. The table below provides a helpful conversion between countries and regions.

Inside Diameter Inside CircumferenceSizes
MMInchesMMInchesBritish & Australian US & CanadaFrench & RussianGermanJapaneseSwiss
9.910.39031.131.220000
10.720.44233.681.3900
11.530.45436.221.430
11.950.47437.541.49A1/2
12.180.48238.261.51A 1/23/4
12.370.48738.861.53B11
12.600.49639.581.56B 1/21 1/4
12.780.50340.151.58C1 1/2
13.000.51240.841.61C 1/21 3/4
13.210.52041.501.63D241 1/213 1/221 1/2
13.410.52842.131.66D 1/22 1/4
13.610.53642.761.68E2 1/242 3/413 3/432 3/4
13.830.54443.451.71E 1/22 3/4
14.050.55344.141.74F3441444
14.150.55744.451.75F 1/23 1/8
14.250.56144.771.76F 3/43 1/4
14.360.56545.111.77G3 3/845 1/455 1/4
14.450.56945.401.79G 1/43 1/214 1/2
14.560.57345.741.80G 1/23 5/86
14.650.57746.021.81H3 3/446 1/26 1/2
14.860.58546.681.84H 1/24157
15.040.59247.251.86I4 1/447 3/47 3/4
15.270.60147.971.89I 1/24 1/215 1/48
15.400.60648.381.90J4 5/84915 1/29
15.530.61148.791.92J 1/44 3/4
15.700.61849.321.94J 1/2515 3/49
15.800.62249.641.95K5 1/85010
15.900.62649.951.97K 1/45 1/4
16.000.63050.271.98K 1/25 3/810
16.100.63450.581.99L5 1/251 3/41611 3/4
16.300.64251.212.02L 1/45 3/4
16.410.64651.552.03L 1/25 7/8
16.510.65051.872.04M652 3/416 1/21212 3/4
16.710.65852.502.07M 1/26 1/4
16.920.66653.162.09N6 1/254171314
17.130.67453.822.12N 1/26 3/4
17.350.68354.512.15O755 1/417 1/41415 1/4
17.450.68754.822.16O 1/27 1/4
17.750.69955.762.20P7 1/256 1/217 3/41516 1/2
17.970.70756.452.22P 1/27 3/4
18.190.71657.152.25Q857 3/4181617 3/4
18.350.72257.652.27Q 1/28 1/4
18.530.72958.212.29Q 3/48 1/218 1/217
18.610.73358.472.30R8 5/85919
18.690.73658.722.31R 1/48 3/4
18.800.74059.062.32R 1/28 7/8
18.890.74859.342.35R 3/491918
19.100.75260.002.36S9 1/860 1/420 1/4
19.220.75760.382.38S 1/49 1/4
19.310.76060.662.39S 1/29 3/8
19.410.76460.982.40S 3/49 1/219 1/219
19.510.76861.292.41T9 5/861 1/221 1/2
19.620.77261.642.43T 1/49 3/4
19.840.78162.332.45T 1/2102020
20.020.78862.892.48U10 1/462 3/42122 3/4
20.200.79763.462.50U 1/210 1/220 1/422
20.320.80063.842.51V10 5/86323 3/4
20.440.80564.212.53V 1/410 3/4
20.680.81464.972.56V 1/21120 3/423
20.760.81765.222.57W11 1/86525
20.850.82165.502.58W 1/411 1/4
20.940.82465.782.59W 1/211 3/8
21.080.83066.222.61W 3/411 1/22124
21.180.83466.542.62X11 5/866 1/426 1/4
21.240.83666.732.63X 1/411 3/4
21.300.83966.922.64X 1/211 7/8
21.490.84667.512.66Y1267 1/221 1/42527 1/2
21.690.85468.142.68Y 1/212 1/4
21.890.86268.772.71Z12 1/268 3/421 3/42628 3/4
22.100.87069.432.73Z +1/212 3/4
22.330.87970.152.76Z+1132227
22.600.89071.002.80Z+1.513.5
22.690.89371.282.81Z+2
22.920.90272.002.83Z+2.5
23.060.90872.452.85Z+3
23.240.91573.012.87Z+3.5
23.470.92473.732.90Z+4
23.550.92773.982.91Z+4.5
23.870.94074.992.95Z+5
24.270.95676.253.00Z+6