Calculations of thermite reaction progress were made using the Cheetah thermochemistry package. Progress was modeled by fractionally substituting reactants with an inert species with identical thermodynamic properties. The results of this model have been used to create a semi-empirical model of regression rate. The acceptability of the D 2 particle regression law for nanothermite systems of a scale on the order of 10 nm has been demonstrated. Additionally a strong sensitivity to composition is demonstrated.