US Ring Size from Diameter in Decimal Inch

Find the size of the ring you need from a diameter measurement of your finger in decimal inches.

This type of ring sizing is used in Canada, Mexico, and the United States.

In addition to the size of the ring you need, this calculator will provide the ring's inside circumference based on your finger's diameter.

The diameter measurement needed is in decimal inch format. The whole number is entered as is, but a fraction has to be converted to a decimal, and you do this by dividing the numerator by the denominator.

example:

2 7/16" = 2 + (7 ÷ 16) = 2.017857 in decimal inches
1 5/8" = 1 + (5 ÷ 8) = 1.625 in decimal inches
1 3/16" = 1 + (3 ÷ 16) 1.1875 in decimal inches

Note:

In this calculator 0.451" is a size 0 ring and at the upper end, 1.41" is a size 30 ring