The particular area of focus for this study is the use of theory to predict the permeability of a material through the use of the Ergun equation and the Kozeny-Carman equation along with computer simulations. The Ergun equation is well known for estimating permeability, and the Kozeny-Carman equation has also beet used to a lesser extent. Existing literature extensively covers the use of these equations with homogeneous materials containing mono-size particles. In this study, ate alternative way is sought to characterize mixtures that is based on the structure of the porosity, or void size, rather than the traditional method of using mean particle diameter. In doing so, this allows the Ergun and Kozeny-Carman equations to be rewritten to provide for an expansion in the type of mixtures that they can be applied to. Results are presented in this article on the application of these equations to mixtures including mono-size particles, then modified to include binary and distributed mixtures.