International Ring Size Conversion Chart

This is the simplest method and only takes a minute:

Cut a strip of paper or grab a piece of string.
Wrap it around the base of your finger.
Mark where the ends meet.
Lay it flat and measure with a ruler (millimeters are best).
Compare your measurement to a ring size chart or by entering the measurement below.

[ring-size-calculator]

Since ring sizes vary between countries, use this chart to compare sizes across different systems:

US/Canada	UK/Australia	Europe	Japan	Inside Diameter (mm)
4	H	46	7	14.8
4.25	H 1/2	47	7.5	15.0
4.5	I	48	8	15.3
4.75	J	49	8.5	15.5
5	J 1/2	50	9	15.7
5.25	K	50.5	9.5	16.0
5.5	K 1/2	51	10	16.2
5.75	L	51.5	10.5	16.4
6	L 1/2	52	11	16.5
6.25	M	53	11.5	16.9
6.5	M 1/2	53.5	12	17.3
6.75	N	54	12.5	17.5
7	N 1/2	55	13	17.7
7.25	O	55.5	13.5	18.0
7.5	O 1/2	56	14	18.2
7.75	P	57	14.5	18.5
8	P 1/2	58	15	18.8
8.25	Q	58.5	15.5	19.0
8.5	Q 1/2	59	16	19.3
8.75	R	60	16.5	19.5
9	R 1/2	61	17	19.8
9.25	S	61.5	17.5	20.1
9.5	S 1/2	62	18	20.3
9.75	T	63	18.5	20.6
10	T 1/2	64	19	20.8
10.25	U	64.5	19.5	21.1
10.5	U 1/2	65	20	21.3
10.75	V	66	20.5	21.6
11	V 1/2	67	21	21.8
11.25	W	67.5	21.5	22.1
11.5	W 1/2	68	22	22.3
11.75	X	69	22.5	22.6
12	X 1/2	70	23	22.8
12.25	Y	71	23.5	23.1
12.5	Y 1/2	72	24	23.3
12.75	Z	73	24.5	23.6