In the framework of k.p theory, we have calculated the expressions for g factors for electrons and holes taking into account up to 16-band contributions for materials with tetragonal symmetry with D 4h as the point group. Because the recent experimental results for Landé factors do not evidence their anisotropy in the plane perpendicular to the tetragonal crystal c axis, we use these experimental results and the present k.p calculations to determine the Kane energies perpendicular to and along the c axis, as well as the Luttinger parameters κ 1 and κ 2 for MAPbI 3 and CsPbBr 3 .