Based on effective medium theory, the Bruggeman equation and Maxwell-Wagner (M-W) equation were applied to extract the permittivity of SrTiO3 and BaTiO3 powders in slurries with various solids loadings. It was found that the margin of error for the calculated permittivity broadened with decreasing solids loading and increasing powder permittivity. However, the margin of error for permittivity calculated from the Bruggeman equation is consistently smaller than that from the M-W equation. This smaller margin of error resulted in the applicability of the Bruggeman equation to extract the permittivity for all of the slurries in this work, in contrast to the M-W equation which is restricted to dilute SrTiO3 slurries. Therefore, for slurries of powders with high permittivity (e.g., BaTiO3) or slurries with high solid loading the Bruggeman equation is necessary instead of the M-W equation.