Ring Size Calculator

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Adjust the ring diameter below to compare US, UK, and EU ring sizes.

This calculator provides an estimated size. For the most accurate recommendation, please contact us .

Inch Diameter Guide

Match the inside edge of your ring, then read the closest size.

Ring Diameter:0.65 in

0.45in0.90in

US: 6

UK: L

EU: 51.8

Use millimeters for the most precise match against the conversion chart.

Ring Diameter:16.50 mm

11mm23mm

US: 6

UK: L

EU: 51.8

Use this chart to compare common US, UK, EU, and diameter measurements. Conversions are approximate.

Ring size conversion chart
Diameter (mm)	Diameter (in)	US	UK	EU
14.1	0.56	3	F	44.3
14.5	0.57	3.5	G	45.6
14.9	0.59	4	H	46.8
15.3	0.60	4.5	I	48.1
15.7	0.62	5	J	49.3
16.1	0.63	5.5	K	50.6
16.5	0.65	6	L	51.8
16.9	0.67	6.5	M	53.1
17.3	0.68	7	N	54.3
17.7	0.70	7.5	O	55.6
18.1	0.71	8	P	56.9
18.5	0.73	8.5	Q	58.1
19.0	0.75	9	R	59.7
19.4	0.76	9.5	S	60.9
19.8	0.78	10	T	62.2
20.2	0.80	10.5	U	63.5
20.6	0.81	11	V	64.7
21.0	0.83	11.5	W	66.0
21.4	0.84	12	X	67.2
21.8	0.86	12.5	Y	68.5
22.2	0.87	13	Z.5	69.7

A well-fitted ring is more comfortable, more secure, and less likely to need avoidable alterations.

A correctly sized ring should feel secure without pinching. Fingers can change slightly with temperature, activity, and time of day.

A loose ring can rotate, catch on clothing, or slip off. The right size helps keep the ring and its setting in a stable position.

Eternity bands, detailed pave designs, engraved bands, and rings with stones around the shank can be difficult to resize.