Moment of Inertia Calculator

This tool works out the area moment of inertia, also called the second moment of area, for the shapes structural sections are usually built from. Pick a rectangle, a rectangular tube, a round bar, a pipe, an I-beam or a T-section, enter its dimensions in any one unit, and it returns Ix and Iy about the centroidal axes together with the polar moment, the elastic section modulus, the radius of gyration and where the centroid sits. A separate action applies the parallel axis theorem on its own, which is what you need to build up a composite shape. The result is section geometry and nothing else: it knows no material, no load and no design code, so it is not a structural check.