Ring Size Converter & Chart

Ring size converter

Convert between UK and Australian letters, US numbers, EU / French, German, Japanese and Swiss sizes, or start from a measurement in millimetres.

The letter and US pairs are the ones in our size menu, chosen from experience fitting our comfort-fit bands, so what you look up here is what you order. Not sure? Choose "I don't know" on any ring and we'll post you a free ring sizer first.

International Ring Size Conversion Chart

Ordering from us? Our size menu pairs each UK letter with a US size, chosen from experience fitting our comfort-fit bands: I / US 4, J / US 4.5, K / US 5, L / US 5.5, M / US 6, N / US 6.5, O / US 7, P / US 7.5, Q / US 8, R / US 8.5, S / US 9, T / US 9.5, U / US 10, V / US 10.5, W / US 11, X / US 11.5, Y / US 12, Z / US 12.5, and Z+1 / US 13 up to Z+7 / US 16. If you know your UK letter or your US size, simply choose it in the menu. The chart below is the general international standard, so its UK and US columns line up slightly differently. Not sure of your size? Choose "I don't know - send free ring sizer" in the size menu.

US Size Inner Diameter (mm) Circumference (mm) British French German Japanese Swiss
2.000 13.19 41.43 D   13.50 2 1.75
2.125 13.29 41.76          
2.250 13.39 42.08 D 1/2 42     2.25
2.375 13.50 42.41          
2.500 13.60 42.73 E   13.75 3 3.00
2.625 13.71 43.06   43      
2.750 13.81 43.38 E 1/2       3.5
2.875 13.91 43.71          
3.000 14.02 44.03 F 44 14 4 4.25
3.125 14.12 44.36          
3.250 14.22 44.68 F 1/2     5 4.75
3.375 14.33 45.01   45      
3.500 14.43 45.34 G   14.50   5.5
3.625 14.53 45.66          
3.750 14.64 45.99 G 1/2 46   6 6.00
3.875 14.74 46.31          
4.000 14.85 46.64 H   15 7 6.75
4.125 14.95 46.96   47      
4.250 15.05 47.29 H 1/2       7.50
4.375 15.16 47.61          
4.500 15.26 47.94 I 48 15.25 8 8
4.625 15.36 48.26     15.50    
4.750 15.47 48.59 J       8.75
4.875 15.57 48.92   49      
5.000 15.67 49.24 J 1/2   15.75 9 9.25
5.125 15.78 49.57          
5.250 15.88 49.89 K 50     10
5.375 15.98 50.22          
5.500 16.09 50.54 K 1/2   16 10  
5.625 16.19 50.87   51      
5.750 16.30 51.19 L       11.25
5.875 16.40 51.52          
6.000 16.50 51.85 L 1/2 52 16.50 11 11.75
6.125 16.61 52.17          
6.250 16.71 52.50 M     12 12.5
6.375 16.81 52.82   53      
6.500 16.92 53.15 M 1/2   17 13 13.25
6.625 17.02 53.47          
6.750 17.12 53.80 N 54     13.75
6.875 17.23 54.12          
7.000 17.33 54.45 N 1/2   17.25 14 14.50
7.125 17.44 54.77   55      
7.250 17.54 55.10 O       15
7.375 17.64 55.43          
7.500 17.75 55.75 O 1/2 56 17.75 15 15.75
7.625 17.85 56.08          
7.750 17.95 56.40 P       16.25
7.875 18.06 56.73   57      
8.000 18.16 57.05 P 1/2   18 16 17.00
8.125 18.26 57.38          
8.250 18.37 57.70 Q 58     17.5
8.375 18.47 58.03          
8.500 18.57 58.35 Q 1/2   18.50 17 18.25
8.625 18.68 58.68   59      
8.750 18.78 59.01 R       19
8.875 18.89 59.33          
9.000 18.99 59.66 R 1/2   19 18 19.5
9.125 19.09 59.98   60      
9.250 19.20 60.31 S       20.25
9.375 19.30 60.63          
9.500 19.40 60.96 S 1/2 61 19.50 19 20.75
9.625 19.51 61.28          
9.750 19.61 61.61 T       21.50
9.875 19.71 61.93   62      
10.000 19.82 62.26 T 1/2   20 20 22
10.125 19.92 62.59          
10.250 20.03 62.91 U 63   21 22.75
10.375 20.13 63.24          
10.500 20.23 63.56 U 1/2   20.25 22 23.25
10.625 20.34 63.89   64      
10.750 20.44 64.21 V       24
10.875 20.54 64.54          
11.000 20.65 64.86 V 1/2 65 20.75 23 24.75
11.125 20.75 65.19          
11.250 20.85 65.51 W       25.25
11.375 20.96 65.84   66      
11.500 21.06 66.17 W 1/2   21 24 26
11.625 21.16 66.49          
11.750 21.27 66.82 X 67     26.5
11.875 21.37 67.14          
12.000 21.48 67.47 X 1/2   21.25 25 27.25
12.125 21.58 67.79   68      
12.250 21.68 68.12 Y       27.75
12.375 21.79 68.44          
12.500 21.89 68.77 Z 69 21.75 26 28.50
12.625 21.99 69.09          
12.750 22.10 69.42 Z 1/2       29
12.875 22.20 69.75          
13.000 22.30 70.07     22 27 29.75
13.125 22.41 70.40          
13.250 22.51 70.72 Z+1       30.5
13.375 22.62 71.05          
13.500 22.72 71.37         31
13.625 22.82 71.70          
13.750 22.93 72.02 Z+2       31.75
13.875 23.03 72.35          
14.000 23.13 72.68 Z+3       32.25
14.125 23.24 73.00          
14.250 23.34 73.33         33
14.375 23.44 73.65          
14.500 23.55 73.98 Z+4       33.5
14.625 23.65 74.30          
14.750 23.75 74.63         34.25
14.875 23.86 74.95          
15.000 23.96 75.28         34.75
15.125 24.07 75.60          
15.250 24.17 75.93         35.5
15.375 24.27 76.26          
15.500 24.38 76.58         36.25
15.625 24.48 76.91          
15.750 24.58 77.23         36.75
15.875 24.69 77.56          
16.000 24.79 77.88         37.5
16.125 24.89 78.21          
16.250 25.00 78.53          
16.375 25.10 78.86          
16.500 25.21 79.18          
16.625 25.31 79.51          
16.750 25.41 79.84          
16.875 25.52 80.16          
17.000 25.62 80.49          
17.125 25.72 80.81          
17.250 25.83 81.14          
17.375 25.93 81.46          
17.500 26.03 81.79          
17.625 26.14 82.11          
17.750 26.24 82.44          
17.875 26.34 82.76          
18.000 26.45 83.09          
18.125 26.55 83.42          
18.250 26.66 83.74          
18.375 26.76 84.07          
18.500 26.86 84.39          
18.625 26.97 84.72          
18.750 27.07 85.04          
18.875 27.17 85.37          
19.000 27.28 85.69          
19.125 27.38 86.02          
19.250 27.48 86.34          
19.375 27.59 86.67          
19.500 27.69 87.00          
19.625 27.80 87.32          
19.750 27.90 87.65          
19.875 28.00 87.97          
20.000 28.11 88.30