Question 434124
If you mean the volume of the tube's material, it's the volume of the cylinder with the OD minus the volume of the cylinder with the ID.
---------
{{{V = pi*r1^2*h - pi*r2^2*h}}} r1 = radius of the outside, r2 = inside
{{{V = pi*h*(r1^2 - r2^2)}}}