Ring Size Guide

A well-fitted ring should feel natural—secure, but never tight. At Forteux, precision matters. We’ve created this guide to help you find the right size with confidence, whether you're choosing a wedding band or an everyday piece.

Our rings are based on UK sizing and an internal diameter in millimetres (Ø). The table below compares these to US and EU sizing. We recommend measuring your size in mm before purchasing.

You may notice there are slight differences between size charts across the web. This is because ring sizing standards, including the UK standard (BS 6820:1987) allows for a manufacturing tolerance of ±0.1mm to ±0.25mm. Therefore, sizing can vary slightly from brand-to-brand and it is important to reference the size guide of any website you buy from.

Ø (mm)	UK	US	EU
13.9	F	3	44
14.3	G	3.5	45.5
14.7	H	4	46.8
15.1	I	4.5	48
15.5	J	5	49.3
15.9	K	5.5	50.6
16.3	L	6	51.8
16.7	M	6.5	53.1
17.1	N	7	54.4
17.5	O	7.5	55.7
17.9	P	8	57
18.3	Q	8.5	58.3
18.7	R	9	59.5
19.1	S	9.5	60.8
19.5	T	10	62.1
19.9	U	10.5	63.4
20.3	V	11	64.6
20.7	W	11.5	65.9
21.1	X	12	67.2
21.5	Y	12.5	68.5
21.9	Z	13	69.7
22.3	Z+1	13.5	71
22.7	Z+2	14	72.3
23.1	Z+3	14.5	73.6