It is well known that the cold-forming process is likely to significantly enhance the mechanical properties of the profile by strain hardening leading to increased resistance compared to a resistance assessment based on nominal properties. It is thus necessary to accurately determine the mechanical properties after the cold process of fabrication. In this paper, experimental reference data and formulae calculating the increased proof strength in cold-formed stainless steel profiles are reviewed. A new theory-based formula for the evaluation of the actual mechanical properties of stainless steel structural members using the virgin sheet material properties is then established. This formula is dependent upon the radius of curvature to thickness ratio; it is not restricted to a single alloy but is valid for non-linear metallic materials. Prediction efficiency is evaluated against the collected experimental data and particular attention is paid to the set of experimental data related to hollow sections. The main thrust of the predictive model lies in its axiomatic roots in contrast to the traditional empirical formulae found in the literature.