Abstract: Wide plates under vertical compression always buckle into a single half-wave， exhibiting lower post-buckling stiffness and strength compared to long plates. This paper introduces the specifications for the bearing capacity of wide plates in the European steel structure design standards， along with finite element analysis results， and proposes a new fitted formula. Vertically-stiffened steel plate walls also exhibit characteristics of wide plates， buckling into a single half-wave under vertical compression. Based on the composition of the elastic buckling resistance， it is found that the buckling resistance of a vertically-stiffened steel plate wall is simply the sum of the stiffeners' individual buckling resistance and that of the unstiffened plate. Based on this property， a new formula for the elastoplastic vertical bearing capacity of vertically-stiffened steel plate walls is proposed.