One of the most important tasks in sheet metal forming is the prediction of formability. The common criterion for ductile fracture in industrial application is the evaluation of the so-called Forming Limit Curve (FLC). The determination of FLCs is standardized in the international standard 12004-2 by two different experimental methods, the Marciniak- and the Nakajima-test. Several effects, for example bending or contact pressure, are leading to biaxial pre-forming and to a slightly non-linear load path. This results in inaccuracies of the FLC. The so-called Generalized Forming Limit Concept (GFLC) is a phenomenological approach, which was introduced to predict the local necking of non-linear load paths. The accuracy and robustness of the GFLC has already been shown in several papers. In this investigation the GFLC was used to compensate the biaxial pre-forming and to calculate a linear FLC. Input parameters are the Marciniak- and Nakajima-FLCs of the material HC340LA.