The Overall Imperfection Method (OIM) is a more comprehensive version of the Unique Global and Local Imperfection Method introduced for steel column design in EN 1993-1-1 standard. The generalized OIM is used to evaluate the stability resistance of steel members subjected to irregular load conditions. This study extensively examines the Overall Imperfection Method (OIM) used in analyzing plate buckling, explicitly focusing on steel grades such as S235, S355 and S460. It compares OIM with methods mentioned in EN 1993-1-5 (Annex B, GMNIA and winter curve). The research carefully validates OIM by analyzing Equation (13) (Annex B) across ratios and studying its behavior with various steel grades. The study highlights the importance of finding a balance when applying OIM regarding material properties and slenderness ratios. These findings provide insights for engineering professionals. Additionally, the research introduces a calibrated equation that allows for the application of OIM without exceeding the limits set by GMNIA. This simplifies its implementation in engineering practice.