- The energetic span model is a bridge connecting the kinetic outcome of experimental and theoretical catalysis. It proves the utility of working with Gibbs energies (E-representation) instead of the rate constants (k-representation), in line with the assertion saying that ‘there are no rate-determining steps, but rate-determining states’. With this model the turnover frequency (TOF), turnover number (TON) and the kinetic determining factors can be obtained from the reaction profile of a computed catalytic cycle. In this way, it is possible to examine, explain, and predict the efficiency of a catalyst. The effect of concentrations, different pathways, preactivation and deactivation, and the comparison of catalysts and reactants are analyzed with several examples from the literature. In addition, the AUTOF program (excel version) is presented, allowing the fast and simple analysis of theoretically calculated catalytic reactions. © 2012 John Wiley & Sons, Ltd.