A calibration system includes a tube or other conduit, a gas source, and a computational device. The tube has an end positioned relative to a flow sensor, and is in communication with the gas source. The tube and gas source introduce calibration gas into the tube at a repeatable mass flow. During a calibration operation, the conduit directs at least a portion of the calibration gas onto the flow sensor. The computational device is used to calculate an estimated flow rate of the calibration gas based upon the measurements obtained from the flow sensor.