A new parameter, the kinetic ratio, is suggested for estimating product potency during storage under ambient warehouse temperatures. Actual warehouse temperature data were integrated using Arrhenius kinetics, and the resulting potency errors, due both to the integration method and to temperature averaging, were evaluated. Kinetic ratios and virtual temperatures then were compared to show seasonal and Arrhenius constant effects. Equations interrelating the kinetic ratio and virtual temperature are given. Finally, sample calculations using typical vitamin A data were analyzed to demonstrate the calculational and interpretation characteristics of the kinetic ratio compared to the virtual temperature.