A compact manometer and nozzle flow meter that compares and demonstrates the accuracy, losses and use of fundamental flow meters. For use by all kinds of engineering students, the Flow Meter Calibration apparatus compares and shows the accuracy and use of fundamental flow meters. The nozzle flow meter or any of the optional flow meters quickly and easily fit into place between the adaptors in the base unit of the apparatus. Students use the hand-pump to increase the air pressure in the manifold. Four water-filled manometers show the pressure differences at the flow meter and across the overall flow meter assembly. The manometers have a common manifold fitted with an air valve.