Find your ring size

Size in MM	US & Canada	Great Britain	Japan	France	Switzerland	Germany
44.1	3	F	4	44	4	14
45.4	3 1/2	G	5	45 1/4	5 1/4	14 1/2
46.7	4	H 1/2	7	46 1/2	6 1/2	15
48.0	4 1/2	I 1/2	8	47 3/4	7 3/4	15 1/2
49.2	5	J 1/2	9	49	9	15 3/4
50.5	5 1/2	K 1/2	10	50 1/4	10 1/4	16 1/4
51.8	6	L 1/2	12	51 1/2	11 1/2	16 1/2
53.1	6 1/2	M 1/2	13	52 3/4	12 3/4	17
54.3	7	O	14	54	14	17 1/4
55.6	7 1/2	P	15	55 1/4	15 1/4	17 3/4
56.9	8	Q	16	56 1/2	16 1/2	18
58.2	8 1/2	R	17	57 3/4	17 3/4	18 1/2
59.4	9	S	18	59	19	19
60.7	9 1/2	--	19	60 1/4	20 1/4	19 1/2
62.0	10	T 1/2	20	61 1/2	21 1/2	20
63.3	10 1/2	U 1/2	22	62 3/4	22 3/4	20 1/2
64.5	11	V 1/2	23	64	24	20 3/4
65.8	11 1/2	W 1/2	24	65 1/4	25 1/4	21
67.1	12	Y	25	66 1/2	26 1/2	21 1/4
68.3	12 1/2	Z	26	67 3/4	27 3/4	21 3/4
69.6	13	--	27	69	29	22

To determine your ring size, do the following:

Use a piece of string or dental floss and wrap it around the base of your finger.
Use a pen to mark the point on the string where the end meets.
Use a millimeter ruler to measure the string.
Choose the closest measurement to the chart above to find your ring size.

Tips for best results:

Allow enough room to accommodate your knuckle.
Bear in mind, different fingers on the same and the opposite hand may have different sizes. Therefore, measure the specific finger on which you are planning to wear the ring.
Measure your finger at the end of the day when your finger is likely to be largest.