The theoretical field positions of the standing spin‐wave modes for selected Permalloy films and YIG films were obtained from a numerical solution of the spin‐wave equation for the case of perpendicular resonance for different pinning conditions. The static magnetizationM(z)was assumed to have an asymmetrical variation in which the magnetization has a minimum value at the substrate‐film interface (z=0) and increases to a maximum value at the film‐air interface (z=L). Comparisons of theoretical and experimental field positions show that a good fit of the experimental data occurs when the magnetization has a polynomial‐type variation.