A new finite-element (FE) method for the determination of differential and apparent inductances of massive conductors is proposed using a sensitivity analysis approach. The new technique is a one-step computation procedure in which the definition of distribution vectors makes possible a unified treatment of solid and filamentary conductors. Since massive conductors are included in the formulation, eddy-current and proximity effects are properly considered. The inductance matrix expression, formally derived from the sensitivity analysis, requires only one evaluation of the Jacobian matrix of the FE system at the solution point. As a result, an efficient calculation can be performed using the same solver employed in the FE solution. The computation of a multiport equivalent of an induction machine has been used to show the power of the proposed method. Our FE and multiport network results have been validated using a well-known commercial FE package.