| Body | Axis | MOI |
|---|---|---|
| Thin rod (M, L) | Centre, perp. | ML^2/12 |
| Thin rod | End, perp. | ML^2/3 |
| Ring (M, R) | Central axis | MR^2 |
| Ring | Diameter | MR^2/2 |
| Disc (M, R) | Central axis | MR^2/2 |
| Disc | Diameter | MR^2/4 |
| Solid sphere (M, R) | Diameter | (2/5)MR^2 |
| Hollow sphere (M, R) | Diameter | (2/3)MR^2 |
| Solid cylinder (M, R) | Central axis | MR^2/2 |
Memory trick: Ring > Hollow sphere > Disc = Solid cylinder > Solid sphere (for same M, R about natural axis). The more mass is concentrated far from the axis, the larger the MOI.