Since real specimens deform three-dimensionally, 2D modeling approaches cannot predict the flow curve of the material precisely. The predicted flow curves obtained from 2D modeling can, however, be correlated to the 3D ones by introducing a correlation factor, We quantified by the stress ratio (σ3D/σ2D) based on the 2D and 3D RVE calculations for DP600 steels with various martensite phase fractions (Vm=0–50%) at different equivalent plastic strains varying from εpeq=0 to 0.1. The correlation is a polynomial equation containing terms for both the martensite fraction and the equivalent plastic strain. In this way, the 3D flow stress of the studied steels was calculated from the 2D stress using our developed correlation factor.