Obtaining the resonance frequency of cutting tools is necessary for dynamic modelling and instability study in milling process. In this paper, two geometrically different endmills are modelled by analytical and Finite Element (FE) approaches and their natural frequencies are calculated. For evaluation of the results, modal testing is carried out. The discrepancies of the analytical results compared to the modal experiments are approximately 25% for both tools. FE results differ 18% and 22% from experimental values for respectively tool 1 and 2. FE values are closer to those of experiment in comparison with analytical results.