Parallel axis theorem

The parallel axis theorem, also known as Huygens–Steiner theorem, or just as Steiner's theorem,^[1] named after Christiaan Huygens and Jakob Steiner, can be used to determine the moment of inertia or the second moment of area of a rigid body about any axis, given the body's moment of inertia about a parallel axis through the object's center of gravity and the perpendicular distance between the axes.