Spheropolyhedra are bodies obtained as Minkowski sums of polyhedra with spheres. They are simple, yet flexible models of non-spherical particles for granular media simulated with the Distinct Element Method (DEM). We here give an analytical method for the calculation of the inertia matrices of convex spheropolyhedra. The special cases of regular spherotetrahedra and arbitrary spherotriangles are addressed and explicit expressions of their inertia matrices are given.