Type the basic major diameter of the tap. I.E. 1/2-13 would be .5

Then type the desired percentage of full thread. Usually between 60 and 80 percent.

Then type the threads per inch of the tap.
I.E. 1/2-13 would be 13

Then click solve.

Here is a list of diameters for # size taps:

0-80 =
1-64 =
1-72 =
2-56 =
2-64 =
3-48 =
3-56 =
4-40 =
4-48 =
5-40 =
5-44 =
6-32 =
6-40 =
8-32 =
8-36 =
10-24 =
10-32 =
12-24 =
12-28 =
