  The photovoltaic and optoelectronic properties of lead halide perovskite
semiconductors are controlled by excitons, so that investigation of their
fundamental properties is of critical importance. The exciton Land\'e or
g-factor g_X is the key parameter, determining the exciton Zeeman spin
splitting in magnetic fields. The exciton, electron and hole carrier g-factors
provide information on the band structure, including its anisotropy, and the
parameters contributing to the electron and hole effective masses. We measure
g_X by reflectivity in magnetic fields up to 60 T for lead halide perovskite
crystals. The materials band gap energies at a liquid helium temperature vary
widely across the visible spectral range from 1.520 up to 3.213 eV in hybrid
organic-inorganic and fully inorganic perovskites with different cations and
halogens: FA_{0.9}Cs_{0.1}PbI_{2.8}Br_{0.2], MAPbI_{3}, FAPbBr_{3}, CsPbBr_{3},
and MAPb(Br_{0.05}Cl_{0.95})_{3}. We find the exciton g-factors to be nearly
constant, ranging from +2.3 to +2.7. Thus, the strong dependences of the
electron and hole g-factors on the band gap roughly compensate each other when
combining to the exciton g-factor. The same is true for the anisotropies of the
carrier g-factors, resulting in a nearly isotropic exciton g-factor. The
experimental data are compared favorably with model calculation results.
