Disclosed is a measuring device for measuring a dielectric constant of filling material in a container. The measuring device includes: a signal generating unit designed to drive a transmitter electrode with an AC voltage such that the transmitter electrode emits a radar signal in the direction of the filling material; a receiver electrode arrangeable in the container to receive the radar signal following passage through the filling material; and an evaluation unit configured to ascertain an amplitude, a phase shift, and/or a signal propagation time between transmitter electrode and receiver electrode on the basis of the received radar signal and to determine the dielectric constant on the basis of the ascertained signal propagation time, phase shift, and/or the amplitude.