Ring Size Converter

Reviewed by the CalculatorHub team, edited by James Graham. General reference guidelines. Last verified 14 June 2026.

Ring sizes vary by country. The United States uses numeric sizes (4-15), the UK and Australia use letters (A-Z plus .5 increments), and Europe uses circumference in millimetres. This reference table provides approximate conversions between US, UK, and EU ring sizes, along with circumference and diameter in millimetres. Measure a ring that fits you or measure your finger circumference directly. These are general guidelines; custom ring sizing may vary slightly from standard measurements.

Ring size conversion table

US	UK/AU	EU	Circ (mm)	Diam (mm)
4	H	47	47.8	15.2
5	J.5	49	49.3	15.7
6	L	51.5	51.9	16.5
7	N	54	54.4	17.3
8	P	57	57.0	18.1
9	R	59	59.5	18.9
10	T	62	62.0	19.7
11	V	64	64.6	20.6
12	X	67	67.2	21.4

How to measure your ring size

Measure the inner circumference of a ring that fits you. Use a flexible ruler or string. Alternatively, measure your finger circumference directly at the widest point. Compare to the table above.

Notes

Ring sizes vary by brand. These are general guidelines. For custom or resizing services, consult a jeweller.

Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.