In order to control correctly robot-assisted surgeries and to avoid compromising the patient's vital organs, the forces exerted over the tissues of the human body must be calculated, monitored and adjusted. In a skin incision, the magnitude of the force depends on the incision’s depth and on the biomechanical properties of skin itself. In this paper, a finite element analysis of the incision and puncture when using a scalpel is presented; its purpose is to calculate the range of forces that can safely be applied with it during a surgery. First, a tension evaluation of puncturing with a scalpel until it completely cuts across the skin was carried out. Then, the stress of performing a 10 mm incision with a surgical scalpel was assessed. The results of these analyses demonstrate that the range of forces that could be applied depends on skin's biomechanical properties and on the condition of the skin sample. In order to perform the puncture, the force should be among the ranges of 0.840 to 8.598 N, while for cutting the skin, the force range is from 0.93 to 10.32 N. This work makes an important contribution for the field of “Computational Analysis of Materials” and “Modeling of Skin Characteristics”.