The invention relates to a device (1) for determining a filling level of a liquid (F) in a container (B), comprising a submersible unit (2) having a pressure sensor unit (3) and a transmitter unit (14) configured as a radio transmitter unit, an ultrasonic transmitter unit or a light signal transmitter unit, and a float unit (5) having a further pressure sensor unit (6) and a further transmitter unit (15) configured as a radio transmitter unit, wherein the further pressure sensor unit (6) is arranged at or in a floating body (7) of the float unit (5) in such a manner that, if the float unit (5) is arranged in the liquid (F) for which the device (1) is intended to determine the filling level, the further pressure sensor unit (6) is arranged below the surface (O) of the liquid (F).