This Master Thesis deals with singly symmetric steel profiles subjected to compressive force. Detaily are analysed centrically and eccentrically loaded hot rolled steel elements with equal leg cross-section. The procedures for determining the buckling load for elements with a compact and slender crosssection according the European Eurocodes and American AISC standards are presented. Featured procedures are used in the calculations of buckling capacity for selected element with a slender crosssection. Influence of residual stresses and geometrical imperfections resulting from the method of manufacture of steel elements, is incorporated in buckling curves. Numerical analysis of buckling behaviour were calculated in numerical environment Abaqus. In numerical simulations material and geometric imperfections were combined in an equivalent geometric imperfection with the corresponding amplitude, so that the results of numerical simulations for centrically loaded elements with a compact cross-section coincide with the corresponding buckling curve in Eurocode standard. Adequacy of the numerical model eccentrically loaded elements was validated by comparing the results of the buckling load by the results of other researchers. The results of numerical simulations centrically and eccentrically loaded elements are further compared with the results calculated according the standards. Proposals for less complicated and more accurate calculations are given for standards.