Japanese Ring Size Guide

CIWAKA jewelry uses Japanese ring sizes. A ring size comparison chart and a Ring Sizing Kit are available to help you determine your Japanese ring size. Most of our ring designs can also be resized after delivery.

Japanese Ring Size Chart

The chart below shows the corresponding measurements for ring sizes on the Japanese and the US scale. If you know your US ring size or ring measurements in millimeters or inches, you can use that information to determine the nearest Japanese ring size. Click the “View Full Chart” button to see Japanese rings sizes 1-30. You can also use the Ring Sizing Kit to get a feel of each Japanese ring size on your finger.

Important Information Regarding Wider Designs >

Japanese Ring Size Guide

Japanese Scale US Scale Inner Circumference Diameter
(JCS) (mm) (inches) (mm) (inches)
1 39.10 1.54 12.45 0.49
1 1/2 40.38 1.59 12.85 0.51
1 40.84 1.61 13.00 0.51
1.5 41.36 1.63 13.17 0.52
2 41.65 1.64 13.26 0.52
2 41.89 1.65 13.33 0.52
2.5 42.41 1.67 13.50 0.53
2 1/2 42.93 1.69 13.67 0.54
3 42.94 1.69 13.67 0.54
3.5 43.46 1.71 13.83 0.54
4 43.98 1.73 14.00 0.55
      3 44.21 1.74 14.07 0.55
4.5 44.51 1.75 14.17 0.56
5 45.03 1.77 14.33 0.56
3 1/2 45.48 1.79 14.48 0.57
5.5 45.55 1.79 14.50 0.57
6 46.08 1.81 14.67 0.58
6.5 46.60 1.83 14.83 0.58
4 46.76 1.84 14.88 0.59
7 47.12 1.86 15.00 0.59
7.5 47.65 1.88 15.17 0.60
4 1/2 48.04 1.89 15.29 0.60
8 48.17 1.90 15.33 0.60
8.5 48.69 1.92 15.50 0.61
9 49.22 1.94 15.67 0.62
5 49.31 1.94 15.70 0.62
9.5 49.74 1.96 15.83 0.62
10 50.27 1.98 16.00 0.63
5 1/2 50.59 1.99 16.10 0.63
10.5 50.79 2.00 16.17 0.64
11 51.31 2.02 16.33 0.64
11.5 51.84 2.04 16.50 0.65
6 51.87 2.04 16.51 0.65
12 52.36 2.06 16.67 0.66
12.5 52.88 2.08 16.83 0.66
6 1/2 53.14 2.09 16.92 0.67
13 53.41 2.10 17.00 0.67
13.5 53.93 2.12 17.17 0.68
7 54.42 2.14 17.32 0.68
14 54.45 2.14 17.33 0.68
14.5 54.98 2.16 17.50 0.69
15 55.50 2.19 17.67 0.70
7 1/2 55.70 2.19 17.73 0.70
15.5 56.03 2.21 17.83 0.70
16 56.55 2.23 18.00 0.71
8 56.97 2.24 18.14 0.71
16.5 57.07 2.25 18.17 0.72
17 57.60 2.27 18.33 0.72
17.5 58.12 2.29 18.50 0.73
8 1/2 58.25 2.29 18.54 0.73
18 58.64 2.31 18.67 0.73
18.5 59.17 2.33 18.83 0.74
9 59.53 2.34 18.95 0.75
19 59.69 2.35 19.00 0.75
19.5 60.21 2.37 19.17 0.75
20 60.74 2.39 19.33 0.76
9 1/2 60.80 2.39 19.35 0.76
20.5 61.26 2.41 19.50 0.77
21 61.78 2.43 19.67 0.77
10 62.08 2.44 19.76 0.78
21.5 62.31 2.45 19.83 0.78
22 62.83 2.47 20.00 0.79
22.5 63.36 2.49 20.17 0.79
10 1/2 63.36 2.49 20.17 0.79
23 63.88 2.51 20.33 0.80
23.5 64.40 2.54 20.50 0.81
11 64.64 2.54 20.57 0.81
24 64.93 2.56 20.67 0.81
24.5 65.45 2.58 20.83 0.82
11 1/2 65.91 2.59 20.98 0.83
25 65.97 2.60 21.00 0.83
25.5 66.50 2.62 21.17 0.83
26 67.02 2.64 21.33 0.84
12 67.19 2.65 21.39 0.84
26.5 67.54 2.66 21.50 0.85
27 68.07 2.68 21.67 0.85
12 1/2 68.47 2.70 21.79 0.86
27.5 68.59 2.70 21.83 0.86
28 69.11 2.72 22.00 0.87
28.5 69.64 2.74 22.17 0.87
13 69.74 2.75 22.20 0.87
29 70.16 2.76 22.33 0.88
29.5 70.69 2.78 22.50 0.89
13 1/2 71.02 2.80 22.61 0.89
30 71.21 2.80 22.67 0.89

Ring Sizng Kit

Ring Sizing Kits can be purchased to measure your Japanese ring size. This kit measures sizes 1-30 on the Japanese scale in one-size increments. Our rings are available in 0.5- or one-size increments depending on the design, and we recommend using the Ring Sizing Kit to test the fit of each Japanese ring size before ordering.

If you purchase a ring after purchasing a Ring Sizing Kit, the price of the kit will be deducted from the price of the ring.

Applying Your Ring Sizing Kit Price Discount

After purchasing a Ring Sizing Kit, you will receive a confirmation email containing a coupon code that can be used later to obtain a corresponding price discount. To receive your price discount, enter the code in the Coupon Code box during checkout when you purchase your ring.

About Coupon Codes

Each Ring Sizing Kit coupon code is valid for one ring purchase only. For any one purchase, only one coupon code may be used. If you have more than one coupon code, each code must be applied to a separate purchase.

    USING YOUR RING SIZING KIT

    Resizing

    If you contact us within 30 days of receipt of your ring with your desired ring size, you can apply for our complimentary resizing service. For designs that cannot be resized, we can provide you with a new ring made to adjusted size at no additional charge. Please note that some ring designs are not eligible for the complimentary resizing or exchange service and will require a resizing fee. For more detailed information regarding resizing, please see the After-Sales service page.

    Please keep in mind that available ring sizes and resizing range vary depending on the design. For information regarding available sizes and resizing range for a particular design, please see the corresponding design page.