A method is presented to quantify the radiated power from a high-density connector. This method is based on network parameters and the principle of conservation of power. Unlike previous work, which assumed only radiated losses were present, the proposed method is able to characterize the radiated power in environments that contain material losses and when there are multiple signals at the printed circuit board/connector interface. The power losses are quantified through the definition of power loss constant matrices that can be used to find the power losses for arbitrary input excitations when the matrices are entirely known. The power loss constant matrices can be calculated through multiple single-port and two-port excitations for an N-port connector. The formulation of these excitations is dictated by the nonlinear properties of the power loss calculation. Simulations and measurements are presented that validate the proposed power loss calculation methodology.