Stainless steel is a material of many specific properties, which significantly differs from carbon steel ones. One of the main attributes of all stainless steel grades that haven't been satisfactorily investigated is the significant change of stress‐strain behaviour due to cold‐forming in fabrication process of structural elements. In the last decades some proposals for the most basic material properties have been developed. However they don't predict the whole stress strain diagram. In the paper presented research involves testing programme focused on virgin and cold‐worked elements of four stainless steel grades: austenitic (1.4404), ferritic (1.4003), duplex (1.4462) and lean duplex (1.4162). Selected grades represent the most used families of stainless steel specified for structural purposes and used for section fabricating via cold‐forming. Gathered data together with other available experimental results serve as a base for analytical part of the research. The main output was establishment of an analytical solution for a stress‐strain diagram of a whole structural cross‐section represented by square and rectangular hollow sections. Further objective was to establish relationships for mechanical properties such as ductility or ultimate strength as these issues have not been sufficiently investigated before. Conclusions contribute to the common design of stainless steel structures and help to precise finite element analyses using enhanced properties of cold‐worked stainless steel.