Buildup factors for photons in infinite homogeneous samples of air, water, and iron have been calculated by a moments method code. The photons were assumed to be emitted from a point source. Comparisons of these results to values obtained earlier, both by experiment and by calculation, show reasonable agreement except in some instances of deep penetration. The parameters in the Berger empirical formula for buildup factors have been evaluated from the present work. The Berger formula is shown to fit the calculational results for nuclei of low atomic number at energies above 1 Me V and below 0.06 MeV. In mid-energy range, differences of as much as 40% are observed. The formula appears to provide excellent fit to the data for nuclei of medium atomic number.