The Moment of Inertia for a Rod rotating about one end assumes that the rod is infinitely thin (but rigid) wire. This is a special case of the the thin rectangular plate with axis of rotation at the end of the plate, with w = L and h = 0. The following formula is used: Iend=mL23, where:
The formula and definition are from Wikipedia (https://en.wikipedia.org/wiki/List_of_moments_of_inertia).