1. Here is chart that can also be considered in determining the appropriate ring size. It measures inside the diameter of such ring in millimeters. This is normally used for double checking your results from the usual paper method. Apart from this, you can also make use of the ring that you wear daily and cross check the same with below chart.
Ring Size (US & Canada) | Diameter |
| Inches | MM |
0.5 |
0.474 |
11.95 |
0.75 |
0.482 |
12.18 |
1 |
0.487 |
12.37 |
1.25 |
0.496 |
12.6 |
1.5 |
0.503 |
12.78 |
1.75 |
0.512 |
13 |
2 |
0.52 |
13.21 |
2.25 |
0.528 |
13.41 |
2.5 |
0.536 |
13.61 |
2.75 |
0.544 |
13.83 |
3 |
0.553 |
14.05 |
3.125 |
0.557 |
14.15 |
3.25 |
0.561 |
14.25 |
3.375 |
0.565 |
14.36 |
3.5 |
0.569 |
14.45 |
3.625 |
0.573 |
14.56 |
3.75 |
0.577 |
14.65 |
4 |
0.585 |
14.86 |
4.25 |
0.592 |
15.04 |
4.5 |
0.601 |
15.27 |
4.625 |
0.606 |
15.4 |
4.75 |
0.611 |
15.53 |
5 |
0.618 |
15.7 |
5.125 |
0.622 |
15.8 |
5.25 |
0.626 |
15.9 |
5.375 |
0.63 |
16 |
5.5 |
0.634 |
16.1 |
5.75 |
0.642 |
16.3 |
5.875 |
0.646 |
16.41 |
6 |
0.65 |
16.51 |
6.25 |
0.658 |
16.71 |
6.5 |
0.666 |
16.92 |
6.75 |
0.674 |
17.13 |
7 |
0.683 |
17.35 |
7.25 |
0.687 |
17.45 |
Ring Size (US & Canada) | Diameter |
| Inches | MM |
7.5 |
0.699 |
17.75 |
7.75 |
0.707 |
17.97 |
8 |
0.716 |
18.19 |
8.25 |
0.722 |
18.35 |
8.5 |
0.729 |
18.53 |
8.625 |
0.733 |
18.61 |
8.75 |
0.736 |
18.69 |
8.875 |
0.74 |
18.8 |
9 |
0.748 |
18.89 |
9.125 |
0.752 |
19.1 |
9.25 |
0.757 |
19.22 |
9.375 |
0.76 |
19.31 |
9.5 |
0.764 |
19.41 |
9.625 |
0.768 |
19.51 |
9.75 |
0.772 |
19.62 |
10 |
0.781 |
19.84 |
10.25 |
0.788 |
20.02 |
10.5 |
0.797 |
20.2 |
10.625 |
0.8 |
20.32 |
10.75 |
0.805 |
20.44 |
11 |
0.814 |
20.68 |
11.125 |
0.817 |
20.76 |
11.25 |
0.821 |
20.85 |
11.375 |
0.824 |
20.94 |
11.5 |
0.83 |
21.08 |
11.625 |
0.834 |
21.18 |
11.75 |
0.836 |
21.24 |
11.875 |
0.839 |
21.3 |
12 |
0.846 |
21.49 |
12.25 |
0.854 |
21.69 |
12.5 |
0.862 |
21.89 |
12.75 |
0.87 |
22.1 |
13 |
0.879 |
22.33 |
13.5 |
0.89 |
22.6 |