Asian ring sizes use a numeric range from 1 to 27 without half or quarter sizes, an Asian ring size 1 corresponds approximately to a US size 1¾ or a UK size D. At the large end of the scale an Asian size 27 corresponds to a US size 13 or a UK size Z½

The sizes start at 1 with an inside diameter of 13mm with each size step being a third of a millimeter, thus the inside diameter of size 2 is 13.333mm, size 3 is 13.666mm and so on.

The Asian ring sizes are widely used across South East Asia including countries such as Japan, China, Hong Kong, Taiwan, Singapore, the Philippines, Vietnam, Thailand and Indonesia.

Asian ring size measurements in inches & millimetres

Size Inner Diameter Inner Circumference   in mm in mm 1 0.511 13.00 1.608 40.84 2 0.525 13.33 1.648 41.88 3 0.538 13.66 1.670 42.91 4 0.551 14.00 1.732 43.98 5 0.564 14.33 1.772 45.02 6 0.577 14.66 1.813 46.06 7 0.591 15.00 1.855 47.12 8 0.604 15.33 1.896 48.16 9 0.617 15.66 1.937 49.18 10 0.630 16.00 1.979 50.26 11 0.643 16.33 2.020 51.30 12 0.656 16.66 2.061 52.34 13 0.669 17.00 2.103 53.41 14 0.682 17.33 2.143 54.44

Size Inner Diameter Inner Circumference   in mm in mm 15 0.695 17.66 2.184 55.48 16 0.709 18.00 2.226 56.55 17 0.722 18.33 2.267 57.59 18 0.735 18.66 2.308 58.62 19 0.748 19.00 2.350 59.69 20 0.761 19.33 2.391 60.73 21 0.774 19.66 2.432 61.76 22 0.787 20.00 2.475 62.83 23 0.800 20.33 2.515 63.87 24 0.813 20.66 2.555 64.91 25 0.827 21.00 2.597 65.97 26 0.840 21.33 2.638 67.01 27 0.853 21.66 2.679 68.05