Sizing a ring is so easy. I found this chart a while ago.
What you will need to size a ring up the way I do it is to take the inside diameter of the ring using callipers,
write that down. Measure the height of the metal, say if it is 2mm you add that to the number you wrote down.
Now whip out that calculator! Take that number and times it by 3.141 or just use the Pi symbol. That number is where you will cut to make the ring the proper size for making your ring.
Here is that chart.
Inside | Inside | Inside | Inside | Number Sizes | Wheat Sheaf | ||
Diameter | Diameter | Circumference | Circumference | US/Canada | British | Japanese | Swiss |
(inches) | (mm) | (inches) | (mm) | Standard | Irish | Equivalent | Equivalent |
Australian | |||||||
Equivalent | |||||||
0.458 | 11.6 | 1.438 | 36.5 | 0 | |||
0.466 | 11.8 | 1.463 | 37.2 | 1/4 | |||
0.474 | 12.0 | 1.488 | 37.8 | 1/2 | A | ||
0.482 | 12.2 | 1.513 | 38.4 | 3/4 | A 1/2 | ||
0.490 | 12.4 | 1.539 | 39.1 | 1 | B | 1 | |
0.498 | 12.6 | 1.564 | 39.7 | 1 1/4 | B 1/2 | ||
0.506 | 12.9 | 1.589 | 40.4 | 1 1/2 | C | ||
0.514 | 13.1 | 1.614 | 41.0 | 1 3/4 | C 1/2 | ||
0.522 | 13.3 | 1.639 | 41.6 | 2 | D | 2 | 1.50 |
0.530 | 13.5 | 1.664 | 42.3 | 2 1/4 | D 1/2 | ||
0.538 | 13.7 | 1.689 | 42.9 | 2 1/2 | E | 3 | 2.75 |
0.546 | 13.9 | 1.714 | 43.5 | 2 3/4 | E 1/2 | ||
0.554 | 14.1 | 1.740 | 44.2 | 3 | F | 4 | 4.00 |
0.562 | 14.3 | 1.765 | 44.8 | 3 1/4 | F 1/2 | 5 | 5.25 |
0.570 | 14.5 | 1.790 | 45.5 | 3 1/2 | G | ||
0.578 | 14.7 | 1.815 | 46.1 | 3 3/4 | G 1/2 | 6 | 6.50 |
0.586 | 14.9 | 1.840 | 46.7 | 4 | H | 7 | |
0.594 | 15.1 | 1.865 | 47.4 | 4 1/4 | H 1/2 | 7.75 | |
0.602 | 15.3 | 1.890 | 48.0 | 4 1/2 | I | 8 | |
0.610 | 15.5 | 1.915 | 48.7 | 4 3/4 | J | 9.00 | |
0.618 | 15.7 | 1.941 | 49.3 | 5 | J 1/2 | 9 | |
0.626 | 15.9 | 1.966 | 49.9 | 5 1/4 | K | 10.00 | |
0.634 | 16.1 | 1.991 | 50.6 | 5 1/2 | K 1/2 | 10 | |
0.642 | 16.3 | 2.016 | 51.2 | 5 3/4 | L | 11.75 | |
0.650 | 16.5 | 2.041 | 51.8 | 6 | L 1/2 | 11 | 12.75 |
0.658 | 16.7 | 2.066 | 52.5 | 6 1/4 | M | 12 | |
0.666 | 16.9 | 2.091 | 53.1 | 6 1/2 | M 1/2 | 13 | 14.00 |
0.674 | 17.1 | 2.116 | 53.8 | 6 3/4 | N | ||
0.682 | 17.3 | 2.141 | 54.4 | 7 | N 1/2 | 14 | 15.25 |
0.690 | 17.5 | 2.167 | 55.0 | 7 1/4 | O | ||
0.698 | 17.7 | 2.192 | 55.7 | 7 1/2 | O 1/2 | 15 | 16.50 |
0.706 | 17.9 | 2.217 | 56.3 | 7 3/4 | P | ||
0.714 | 18.1 | 2.242 | 56.9 | 8 | P 1/2 | 16 | 17.75 |
0.722 | 18.3 | 2.267 | 57.6 | 8 1/4 | Q | ||
0.730 | 18.5 | 2.292 | 58.2 | 8 1/2 | Q 1/2 | 17 | |
0.738 | 18.7 | 2.317 | 58.9 | 8 3/4 | R | 19 | |
0.746 | 18.9 | 2.342 | 59.5 | 9 | R 1/2 | 18 | |
0.754 | 19.2 | 2.368 | 60.1 | 9 1/4 | S | 20.25 | |
0.762 | 19.4 | 2.393 | 60.8 | 9 1/2 | S 1/2 | 19 | |
0.770 | 19.6 | 2.418 | 61.4 | 9 3/4 | T | 21.5 | |
0.778 | 19.8 | 2.443 | 62.1 | 10 | T 1/2 | 20 | |
0.786 | 20.0 | 2.468 | 62.7 | 10 1/4 | U | 21 | |
0.794 | 20.2 | 2.493 | 63.3 | 10 1/2 | U 1/2 | 22 | 22.75 |
0.802 | 20.4 | 2.518 | 64.0 | 10 3/4 | V | ||
0.810 | 20.6 | 2.543 | 64.6 | 11 | V 1/2 | 23 | |
0.818 | 20.8 | 2.569 | 65.2 | 11 1/4 | W | 25 | |
0.826 | 21.0 | 2.594 | 65.9 | 11 1/2 | W 1/2 | 24 | |
0.834 | 21.2 | 2.619 | 66.5 | 11 3/4 | X | ||
0.842 | 21.4 | 2.644 | 67.2 | 12 | X 1/2 | 25 | 27.50 |
0.850 | 21.6 | 2.669 | 67.8 | 12 1/4 | Y | ||
0.858 | 21.8 | 2.694 | 68.4 | 12 1/2 | Z | 26 | 28.75 |
0.866 | 22.0 | 2.719 | 69.1 | 12 3/4 | Z 1/2 | ||
0.874 | 22.2 | 2.744 | 69.7 | 13 | 27 | ||
0.882 | 22.4 | 2.769 | 70.3 | 13 1/4 | Z1 | ||
0.890 | 22.6 | 2.795 | 71.0 | 13 1/2 | |||
0.898 | 22.8 | 2.820 | 71.6 | 13 3/4 | Z2 | ||
0.906 | 23.0 | 2.845 | 72.3 | 14 | Z3 | ||
0.914 | 23.2 | 2.870 | 72.9 | 14 1/4 | |||
0.922 | 23.4 | 2.895 | 73.5 | 14 1/2 | Z4 | ||
0.930 | 23.6 | 2.920 | 74.2 | 14 3/4 | |||
0.938 | 23.8 | 2.945 | 74.8 | 15 | |||
0.946 | 24.0 | 2.970 | 75.4 | 15 1/4 | |||
0.954 | 24.2 | 2.996 | 76.1 | 15 1/2 | |||
0.962 | 24.4 | 3.021 | 76.7 | 15 3/4 | |||
0.970 | 24.6 | 3.046 | 77.4 | 16 |