The current study proposes an empirical formula for absorption buildup factors as a function of target thickness. The present formula produces absorption buildup factors of compounds and mixtures with simple inputs of linear attenuation coefficient (μ), tenth value layer (TVL) and half value layer (HVL) of interacting target for the atomic number region 29 < Z < 92 for the energies 0.2 MeV < E < 1.5 MeV. This method is used to compute the energy absorption buildup factors using HVL and TVL.