A consistent kinematic method was developed to calculate a forming limit curve (FLC) for a material with thickness t * 0 from a given FLC pertaining to a different thickness t 0 ≠ t * 0 . The developed method is based on the analysis of the bending strains introduced by the Nakajima test method. To calculate the required strains, an explicit and an implicit procedure are presented. In contrast to its implicit equivalent, the explicit method suffers from an intrinsic error which scales with the material’s gauge and can be quantified by considering the neutral case t * 0 = t 0 . Finally, the developed method predicts a linear relationship between and the material thickness, which is in line with practical experience.