Abstract Transformation rules are given that take the concentration or current expressions for the simple irreversible electron-transfer reaction R → P + e − and convert them to the corresponding quantities for the quasireversible reaction. They apply for many standard electrochemical mass-transport cases, including simple diffusion and convection-diffusion for the rotating disk or channel flow, provided that the diffusivities of the two species are equal. The forward rate constant is replaced by the sum of the forward and reverse rate constants, the result is scaled and then a constant added. Rules are also given for some cases where the diffusivities are unequal. As an application, a new solution of the concentration profile for a channel electrode within the Leveque approximation neglecting axial diffusion is given.