Considering variation of influent factors is a critical issue to enhance the robustness of sheet metal forming process in the product design process. The stochastic variability of uncontrollable factors results in the variations on the formed part which can lead to rejected parts. Since the inherent sources of variation in the sheet metal forming process comes from part-to-part, within batch and batch-to-batch variation. Therefore, the prediction and control of the variability influencing on the performance of the product is an essential demand of automotive and aeronautic manufacturers. Moreover, it is very necessary to have a numerically dedicated tool which predicts the process variability with a good confidence. In this paper, prediction of the variations of the formed part due to the variabilities of the sheet stamping process and the workpiece by numerical simulation will be carried out.