THIN-WALL THIN-WALL is a user-friendly computer program for calculating the section properties and stresses in thin-walled cross-sections of general geometry. The program calculates the section properties, sectorial coordinate, and the longitudinal and shear stresses for the cross-section. THIN-WALL can also perform an elastic buckling analysis of thin-walled structures subjected to longitudinal stress. The structure being analysed may be a folded plate system, a stiffened plate or a thin-walled structural member but it must be uniform in thickness in the longitudinal direction and simply supported at its ends. The longitudinal edges may be simply supported, clamped or free along the full length of the plate system. The analysis can be done for a number of different buckle half-wavelengths of the structure and the load factor and buckled shape are output for each length.