# Parallel-axis theorem

To find the moment-of-inertia $I$ of an object about any axis, find the moment-of-inertia about a parallel axis through the centre-of-mass $I_\mathrm{com}$ and add a term that covers the distance $d$ from new axis-of-rotation to centre-of-mass as well as the total mass $m$ of the object:

$$I= I_\mathrm{com} +dm^2$$