Current‐potential (i‐E) curves for the electrochromic process at electrodes were calculated with a digital simulation model which assigns the rate of charge transfer at the oxide/solution interface and the rate of diffusion of hydrogen into the bulk of the film as major variables. The simulated i‐E curves agreed well with experimental ones for different types of films and predicted the observed dependency of current on scan rate. The simulation required knowledge of the form of the electrochemical isotherm, which was obtained experimentally, and adjustment of a charge transfer rate constant, , and the hydrogen atom diffusion coefficient within the film, . The best fit was obtained with and for the films prepared by vacuum evaporation and and for anodic films. Simulated potential step results, which are similar to the experimental curves at longer times but show some discrepancy in the short time region, and concentration profiles are also reported.