Japanese Ring Size Conversion Chart

The Japanese ring size system is the most popular in Asia as it is used by many countries, including Japan, China, Korea, Taiwan and Singapore but converting to US or European sizes can be challenging, which is why we created a free, easy-to-use conversion tool that shows you the nearest sizes in other standards.

To use the ring size conversion tool, simply:

Select the size standard from the dropdown list (it defaults to Japanese Sizes on this page)
Select the ring size
Then the tool will show you the exact or closest matches in the other size standards and allows you to see the small differences in sizes between the closest matched sizes

Japanese Ring Size Conversion Chart

If you prefer to use a table, then we have also included a full Japanese ring size conversion chart that shows:

Japanese to US ring sizes
Japanese to European ring sizes (used by Germany, France and Scandinavian countries)
Japanese to Swiss ring sizes (also used in Spain and Italy)
Japanese to UK ring sizes (also used in China, Korea and Singapore)
Japanese to Brazilian ring sizes

Japan	USA/Canada	UK/Australia	Europe	Switzerland	Brazil	Diameter (mm/in)	Circumference (mm/in)
1	1.75	C			13.0 mm / 0.51 in	40.8 mm / 1.61 in
2	2.25	D				13.3 mm / 0.52 in	41.9 mm / 1.65 in
3	2.75	E				13.7 mm / 0.54 in	42.9 mm / 1.69 in
4	3	E 1/2	44	4	7	14.0 mm / 0.55 in	44.0 mm / 1.73 in
5	3.5	F 1/2	45	4.5	8	14.3 mm / 0.56 in	45.0 mm / 1.77 in
6	3.75	G 1/2	46	5	9	14.7 mm / 0.58 in	46.1 mm / 1.81 in
7	4	H	47	5.5	10	15.0 mm / 0.59 in	47.1 mm / 1.85 in
8	4.5	I	48	6	11	15.3 mm / 0.60 in	48.2 mm / 1.90 in
9	4.75	J	49	6.5	12	15.6 mm / 0.61 in	49.2 mm / 1.94 in
10	5.25	K	50	7	13	15.9 mm / 0.63 in	50.3 mm / 1.98 in
11	5.75	L	51	7.5	14	16.3 mm / 0.64 in	51.3 mm / 2.02 in
12	6.25	M	52	8	15	16.6 mm / 0.65 in	52.4 mm / 2.06 in
13	6.5	M 1/2	53	8.5	16	17.0 mm / 0.67 in	53.4 mm / 2.10 in
14	7	N 1/2	54	9	17	17.3 mm / 0.68 in	54.5 mm / 2.15 in
15	7.5	O 1/2	56	10	19	17.7 mm / 0.70 in	55.5 mm / 2.19 in
16	7.75	P				18.0 mm / 0.71 in	56.6 mm / 2.23 in
17	8.25	Q	57	10.5	20	18.3 mm / 0.72 in	57.6 mm / 2.27 in
18	8.75	R	59	11.5	22	18.7 mm / 0.74 in	58.6 mm / 2.31 in
19	9	R 1/2	60	12	23	19.0 mm / 0.75 in	59.7 mm / 2.35 in
20	9.5	S 1/2	61	12.5	24	19.4 mm / 0.76 in	60.7 mm / 2.39 in
21	9.75	T	62	13	25	19.7 mm / 0.78 in	61.8 mm / 2.43 in
22	10.5	U 1/2	63	13.5	26	20.1 mm / 0.79 in	62.8 mm / 2.47 in
23	10.75	V	64	14	27	20.4 mm / 0.80 in	63.9 mm / 2.52 in
24	11	V 1/2	65	14.5	28	20.7 mm / 0.81 in	64.9 mm / 2.56 in
25	11.25	W 1/2	66	15	29	21.0 mm / 0.83 in	66.0 mm / 2.60 in
26	11.75	X 1/2	67	15.5	30	21.4 mm / 0.84 in	67.0 mm / 2.64 in
27	12.25	Y 1/2	68	16	31	21.7 mm / 0.85 in	68.1 mm / 2.68 in
28	12.5	Z 1/2	69	16.5	32	22.0 mm / 0.87 in	69.1 mm / 2.72 in
29	13		70	17	33	22.3 mm / 0.88 in	70.2 mm / 2.76 in
30		Z+1			34	22.7 mm / 0.89 in	71.2 mm / 2.80 in

Japan

USA/Canada

UK/Australia

Europe

Switzerland

Brazil

Diameter
(mm/in)

Circumference
(mm/in)

1.75

13.0 mm / 0.51 in

40.8 mm / 1.61 in

2.25

13.3 mm / 0.52 in

41.9 mm / 1.65 in

2.75

13.7 mm / 0.54 in

42.9 mm / 1.69 in

E 1/2

14.0 mm / 0.55 in

44.0 mm / 1.73 in

3.5

F 1/2

4.5

14.3 mm / 0.56 in

45.0 mm / 1.77 in

3.75

G 1/2

14.7 mm / 0.58 in

46.1 mm / 1.81 in

5.5

15.0 mm / 0.59 in

47.1 mm / 1.85 in

4.5

15.3 mm / 0.60 in

48.2 mm / 1.90 in

4.75

6.5

15.6 mm / 0.61 in

49.2 mm / 1.94 in

5.25

15.9 mm / 0.63 in

50.3 mm / 1.98 in

5.75

7.5

16.3 mm / 0.64 in

51.3 mm / 2.02 in

6.25

16.6 mm / 0.65 in

52.4 mm / 2.06 in

6.5

M 1/2

8.5

17.0 mm / 0.67 in

53.4 mm / 2.10 in

N 1/2

17.3 mm / 0.68 in

54.5 mm / 2.15 in

7.5

O 1/2

17.7 mm / 0.70 in

55.5 mm / 2.19 in

7.75

18.0 mm / 0.71 in

56.6 mm / 2.23 in

8.25

10.5

18.3 mm / 0.72 in

57.6 mm / 2.27 in

8.75

11.5

18.7 mm / 0.74 in

58.6 mm / 2.31 in

R 1/2

19.0 mm / 0.75 in

59.7 mm / 2.35 in

9.5

S 1/2

12.5

19.4 mm / 0.76 in

60.7 mm / 2.39 in

9.75

19.7 mm / 0.78 in

61.8 mm / 2.43 in

10.5

U 1/2

13.5

20.1 mm / 0.79 in

62.8 mm / 2.47 in

10.75

20.4 mm / 0.80 in

63.9 mm / 2.52 in

V 1/2

14.5

20.7 mm / 0.81 in

64.9 mm / 2.56 in

11.25

W 1/2

21.0 mm / 0.83 in

66.0 mm / 2.60 in

11.75

X 1/2

15.5

21.4 mm / 0.84 in

67.0 mm / 2.64 in

12.25

Y 1/2

21.7 mm / 0.85 in

68.1 mm / 2.68 in

12.5

Z 1/2

16.5

22.0 mm / 0.87 in

69.1 mm / 2.72 in

22.3 mm / 0.88 in

70.2 mm / 2.76 in

Z+1

22.7 mm / 0.89 in

71.2 mm / 2.80 in