Ring Size Guide

At Diamond Boutique, we understand that finding the perfect fit is extremely important and difficult, especially if it's a surprise, that's why we have a created a simple and easy-to-understand ring size guide.

Please use the guide below to help you find the right ring size, this table shows the inside circumference and diameter of each ring size.

If you are still struggling and/or require a bespoke size, feel free to contact us on 0203 6959 885 and we will work with you to ensure you find the perfect ring with the perfect fit.

Inside diameterInside circumferenceSizes
(in)(mm)(in)(mm)United States and CanadaUnited Kingdom, Ireland,
Australia and
New Zealand
India, China, Japan,
South America
Italy, Spain, Netherlands, Switzerland
0.53 13.46 1.67 42.3   2.25
0.538 13.67 1.69 42.9 E 3 3
0.546 13.87 1.72 43.6   3.5
0.554 14.07 1.74 44.2 3 F 4 4.25
0.562 14.27 1.77 44.8 5 4.75
0.57 14.48 1.79 45.5 G   5.5
0.578 14.68 1.82 46.1 6 6
0.586 14.88 1.84 46.8 4 H 7 6.75
0.594 15.09 1.87 47.4   7.5
0.602 15.29 1.89 48 I 8 8
0.61 15.49 1.92 48.7 J   8.75
0.618 15.7 1.94 49.3 5 9 9.25
0.626 15.9 1.97 50 K   10
0.634 16.1 1.99 50.6 10 10.5
0.642 16.31 2.02 51.2 L   11.25
0.65 16.51 2.04 51.9 6 11 11.75
0.658 16.71 2.07 52.5 M 12 12.5
0.666 16.92 2.09 53.1 13 13.25
0.674 17.12 2.12 53.8 N   13.75
0.682 17.32 2.14 54.4 7 14 14.5
0.69 17.53 2.17 55.1 O   15
0.698 17.73 2.19 55.7 15 15.75
0.706 17.93 2.22 56.3 P   16.25
0.714 18.14 2.24 57 8 16 17
0.722 18.34 2.27 57.6 Q   17.5
0.73 18.54 2.29 58.3 17 18.25
0.738 18.75 2.32 58.9 R   19
0.746 18.95 2.34 59.5 9 18 19.5
0.754 19.15 2.37 60.2 S   20.25
0.762 19.35 2.39 60.8 19 20.75
0.77 19.56 2.42 61.4 T   21.5
0.778 19.76 2.44 62.1 10 20 22
0.786 19.96 2.47 62.7 10¼ U 21 22.75
0.794 20.17 2.49 63.4 10½ 22 23.25
0.802 20.37 2.52 64 10¾ V   24
0.81 20.57 2.54 64.6 11 23 24.75
0.818 20.78 2.57 65.3 11¼ W   25.25
0.826 20.98 2.59 65.9 11½ 24 26
0.834 21.18 2.62 66.6 11¾ X   26.5
0.842 21.39 2.65 67.2 12 25 27.25
0.85 21.59 2.67 67.8 12¼ Y   27.75
0.858 21.79 2.7 68.5 12½ Z 26 28.5
0.866 22 2.72 69.1 12¾   29
0.874 22.2 2.75 69.7 13   27 29.75
0.882 22.4 2.77 70.4 13¼ Z1   30.5
0.89 22.61 2.8 71 13½     31
0.898 22.81 2.82 71.7 13¾ Z2   31.75
0.906 23.01 2.85 72.3 14 Z3   32.25
0.914 23.22 2.87 72.9 14¼     33
0.922 23.42 2.9 73.6 14½ Z4   33.5
0.93 23.62 2.92 74.2 14¾     34.25
0.938 23.83 2.95 74.8 15     34.75
0.946 24.03 2.97 75.5 15¼     35.5
0.954 24.23 3 76.1 15½     36.25
0.962 24.43 3.02 76.8 15¾     36.75
0.97 24.64 3.05 77.4 16     37.5