An analytical method to calculate the efficiency of VSC-HVDC links based on two-level and three-level VSCs is presented. The method uses the average and root mean square of the VSC converter current to estimate the conversion losses in the converters (conduction and switching losses). The remaining power losses (DC cable transmission losses due to , the losses in the coupling transformer, and AC harmonic filter losses) are evaluated using conventional well-known methods. Results obtained analytically are confirmed by digital simulations.