For a full cubic unit cell with formula A 8 B 16 O 32 , 24 cations are distributed across 16 octahedral and 8 tetrahedral sites. Using combinatorics there are total of 8!16! = 735, 471 possible cationic configurations. Although this calculation does not include symmetry, assumes unique elements and disregards the distribution of atoms over the tetrahedral sites, the result gives a sense of scale of the number of configurations that need to be considered to fully capture all possible configurations for a simple binary spinel. Table shows the distribution of inversion for structures of a generic A 8 B 16 O 32 unit cell generated by random swapping of cations and represents an upper bound of the number of structures. These many possible configurations are possible due to inversion of cations in the structure. Pilania and coworkers explore nearly 160,000 spinel configurations in the Mg-Al-Ga-In-O phase field using a cluster-expansion based effective Hamiltonian. Of these, only 350 configurations are explored using DFT methods. This work gives an idea of the scale of DFT calculations that can be reasonably be conducted for a given system.