PurposeTo evaluate mild steel corrosion using a new surfactant‐inhibition model which was derived, in part, from the concept of intermolecular energy and molecular separation distance.Design/methodology/approachA Gamry potentiostat was used for polarization resistance tests to determine corrosion rate and the level of adsorption of surfactant at the solution‐metal interface was determined using UV‐spectroscopy. The relationship between inhibition and surfactant adsorption as well as metal corrosion was investigated using a traditional surfactant‐inhibition model, which assumes inhibition is directly proportional to surfactant coverage and new model.FindingsThe comparison of adsorption data and corrosion inhibition data shows inhibition was not directly proportional to physical coverage as assumed by the traditional inhibition model. Instead, it was found that coverage was related to inhibition through a power‐law dependency that is similar to that used to determine molecular interaction energies.Research limitations/implicationsThe new model was evaluated only for dodecyl pyridinium chloride mild steel system. The evaluation of the new model for various surfactant‐metal systems is suggested for future research.Originality/valueThe new model was found to more accurately predict the relationship between inhibition and coverage rather than traditional models for dodecyl pyridinium chloride‐mild steel system.