Torus Radius, Circumference and Diameter in Blender

• I'd say, use curves instead as one way at least. That way you create bezier circle, set its bevel radius to your 1'', set its scale so (once radius is in place values in the T panel > Tool > dimensions in object mode will give correct result). Once satisfied convert to mesh, add Solidify modifier (you can do that with curves too if using a curve object consisting of 2 circles as bevel object for the main curve). Another way maybe would be geometry nodes Nov 2, 2021 at 20:43

If you set the Dimension Mode to Major/Minor then a 46" Diameter Torus with a with a 1" outer diameter tube would be specified as Major Radius = 23" and Minor Radius = .5":

That is, in answer to your question, using Major/Minor, the Major Radius is the radius of the circle that is aligned with the center of the torus and the Minor Radius is the radius of the circle that is the cross section of the torus.

In the Item display in the side panel, this object will appear as 47" x 47" x 1" because that is the size of the Bounding Box:

It is 47" because the outer diameter of the torus consists of the diameter of the central circle (2 x 23 = 46) + the diameter of the cross section (2 x .5 = 1), since one half of the cross section extends beyond the center in each dimension of x and y. The Z dimension is 1 because that's the diameter of the cross section.