The master flowmeter is providing accurate and easy calibration of LPG dispensers within temperature range of -20°C to +40°C. The unit is build on special frame together with the measurement, control and safety devices. The actual flow out is indicated electronically as dispenser nozzle is connected to the inlet socket of the master-flowmeter. The measured fuel is returned to the dispenser using special test cap. The device also measures fluid pressure and temperature, providing information for dispenser calibration.