The continuous magnetization of a 180° one‐dimensional interdomain wall in a ferromagnetic thin film is replaced by a discrete distribution for which the magnetostatic energy can be calculated rigorously. The general functional form of the direction of magnetization within the wall is not restricted by this replacement, and minimization of the total energy with the aid of a digital computer yields both the equilibrium wall structure and its corresponding energy. It is found that only Bloch and Ne´el types of one‐dimensional walls result. The magnetization distribution of a typical Bloch wall is shown, and the Bloch wall energy and wall thickness are calculated as functions of film thickness and compared with values from the literature. Finally, some detail of the Ne´el wall structure is presented, and it is shown that the transition from one‐dimensional Bloch to Ne´el walls should occur at much larger film thickness than has been reported previously.