Equations for the calculation of the equivalent circuit parameters of the piezoelectric resonator are presented. The results from both eigen-frequency and frequency response analyses could be used for calculating the electrical parameters of the Butterworth Van Dyke model of the piezoelectric resonator. The values of the electrical parameters C1, and L1 obtained from both types of analyses were found to be similar, and were found to compare reasonably well with the measured values of two 12 MHz AT-cut quartz resonators. The values of R1, and Q were less well predicted when the resonator has a lower Q. The static capacitance C0 could be calculated accurately by its frequency response at 1 Hz. The eigen-frequency analysis is better suited than the frequency response analysis for the study of electrode and plate geometry designs, hence the eigen-frequency equations for calculating the equivalent circuit parameters are more useful for parametric designs.