I z = 1 2 m ( r 2 2 + r 1 2 ) = m r 2 2 ( 1 − − t + t 2 2 ) where t = (r 2 − r 1)/ r 2 is a normalized thickness ratio; I x = I y = 1 12 m ( 3 ( r 2 2 + r 1 2 ) + h 2 ) The above formula is for the xy plane passing through the center of mass, which coincides with the geometric center of the cylinder. If the xy plane is at the base of the cylinder, i.e. offset by d = h 2 , then by the parallel axis theorem the following formula applies: I x = I y = 1 12 m ( 3 ( r 2 2 + r 1 2 ) + 4 h 2 )