A method for measuring s-parameters of an N-port device under test (DUT), using an N-port test fixture and a network analyzer. The method includes: measuring calibration errors of the N-port test fixture using a reduced set of N/2 calibration standards; measuring calibration errors due to the network analyzer by calibrating only the network analyzer using analyzer-only calibration standards; isolating test fixture s-parameters errors using results of the analyzer-only calibration standards measurement and the N-port test fixture calibration standard measurement; measuring the s-parameters errors of the DUT; and correcting the s-parameters errors of the DUT corresponding to the isolated test fixture s-parameters errors and the calibration errors of the network analyzer.