The present invention relates to a system, method, and computer program product for determining the flow rate of a fluid. The system, method, and computer program product generate a thermal sensor based mass flow rate for the fluid, where the thermal sensor based mass flow rate is determined at least in part from the thermal sensor signal (36). The system, method, and computer program product generate a pressure sensor based mass flow rate for the fluid, wherein the pressure sensor based mass flow rate is determined at least in part from the pressure sensor signal (51a). The system, method, and computer program product generate at least one calibration factor (ψ) using the thermal sensor based mass flow rate and the pressure sensor based mass flow rate. The system, method, and computer program product may generate a calibrated pressure sensor based mass flow rate by using the at least one calibration factor (ψ) to modify the pressure sensor based mass flow rate. The system, method, and computer program product may generate a calibrated thermal sensor based mass flow rate by using the at least one calibration factor (ψ) to modify the thermal sensor based mass flow rate.