The present invention discloses a beverage machine (1) comprising a tank (2), which holds a liquid for preparing a beverage, and a dispenser (7), to which the tank is connectable, wherein the tank (2) comprises a valve (8); the dispenser comprises an opening (9) for receiving the valve in connection of the tank on the dispenser; at least one ultrasonic transceiver (3) is disposed in the dispenser (7) or tank (2), the ultrasonic transceiver being designed to emit and receive ultrasonic waves (4a, 4b) in the liquid, in order to determine the distance (d) from the transceiver to the liquid level (5), wherein it further comprises a control unit (6), which is connected to the ultrasonic transceiver (3) which is adapted to determine the distance (d) changing with time and as a result the volume (V) of the liquid flowing out of the tank.