Japanese Ring Size Conversion Calculator & Table – 2025 (Japan, US, UK)

Getting your ring size right is one of the most important steps when buying jewelry. A ring that’s too loose can easily slip off and get lost, while one that’s too tight is uncomfortable and difficult to remove.

On this page, you will find our free Japanese ring size conversion calculator to help you convert your Japanese ring size to all other international ring size regions. This will help you choose the correct ring size from any online jewelry store, without any worries.

Japanese Ring Size Conversion Calculator

To use the Japanese Ring Size Conversion Calculator, simply select your Japanese ring size from the dropdown bar below, and see the equivalent units for Europe, the US, and Asia, among other regions.

If you know your ring size in a different format, you can use our other dedicated conversion tools. We have calculators based on the UK (Letter), US (Numerical), EU (Circumference), and Swiss standards.

Once you have found your perfect size, we invite you to view our list of handmade silver filigree rings and silver opal rings.

Japanese Ring Size Conversion Chart

Japan, China & S. America	US & Canada	UK & Australia	EU (Inner Circumference in mm)	Switzerland
0.5*	0.5	A	37.5	<0*
0.8*	0.75	A ½	38.2	<0*
1	1	B	38.9	<0*
1.5*	1.25	B ½	39.5	<0*
2	1.5	C	40.2	0.2
2.5*	1.75	C ½	40.8	0.8
3	2	D	41.5	1.5
3.5*	2.25	D ½	42.1	2.1
4	2.5	E	42.8	2.8
4.5*	2.75	E ½	43.4	3.4
5	3	F	44.1	4.1
5.5*	3.25	F ½	44.7	4.7
6	3.5	G	45.4	5.4
7	3.75	G ½	46.0	6.0
8	4	H	46.7	6.7
8.5*	4.25	H ½	47.3	7.3
9	4.5	I	48.0	8.0
9.5*	4.75	I ½	48.6	8.6
10	5	J	49.2	9.2
10.5*	5.25	J ½	49.9	9.9
11	5.5	K	50.5	10.5
11.5*	5.75	K ½	51.2	11.2
12	6	L	51.8	11.8
12.5*	6.25	L ½	52.5	12.5
13	6.5	M	53.1	13.1
13.5*	6.75	M ½	53.8	13.8
14	7	N	54.4	14.4
14.5*	7.25	N ½	55.1	15.1
15	7.5	O	55.7	15.7
15.5*	7.75	O ½	56.4	16.4
16	8	P	57.0	17.0
16.5*	8.25	P ½	57.6	17.6
17	8.5	Q	58.3	18.3
17.5*	8.75	Q ½	58.9	18.9
18	9	R	59.6	19.6
18.5*	9.25	R ½	60.2	20.2
19	9.5	S	60.9	20.9
19.5*	9.75	S ½	61.5	21.5
20	10	T	62.2	22.2
21	10.25	T ½	62.8	22.8
22	10.5	U	63.5	23.5
22.5*	10.75	U ½	64.1	24.1
23	11	V	64.7	24.7
23.5*	11.25	V ½	65.4	25.4
24	11.5	W	66.0	26.0
24.5*	11.75	W ½	66.7	26.7
25	12	X	67.3	27.3
25.5*	12.25	X ½	68.0	28.0
26	12.5	Y	68.6	28.6
26.5*	12.75	Y ½	69.2	29.2
27	13	Z	69.9	29.9
27.5*	13.25	Z ½	70.5	30.5
28	13.5	Z+1	71.2	31.2
29*	14	Z+2	72.5	32.5
30*	14.5	Z+3	73.7	33.7
31*	15	Z+4	74.8	34.8
32*	15.5	Z+5	76.0	36.0
33*	16	Z+6	76.9	36.9

Disclaimer: Values marked with an asterisk (*) are approximated as a direct, standardized equivalent is not available. Values marked as <0* are for sizes that are smaller than the official starting point of the Swiss sizing system and are mathematical extrapolations. These units were measured based on international ring size standards.

Armed with this comprehensive conversion chart and easy-to-use calculator, you can now shop for rings from Japanese brands and retailers with complete confidence.

Finding your perfect fit is no longer a matter of guesswork. By taking a moment to accurately convert your size, you ensure that the beautiful ring you choose will be comfortable, secure, and ready to wear the moment it arrives. Happy shopping, and enjoy exploring the unique and exquisite designs of Japanese jewelry.

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