A method for measuring by means of a radar measuring device a volume flow of a medium transported by a conveyor belt, wherein the radar measuring device is arranged and oriented such that a main emission direction (H 1) of the radar measuring device includes with a direction of a surface normal of the conveyor belt a first angle (α), wherein the first angel (α) is greater than 0° and smaller than 90°, and includes with a transport direction of the conveyor belt a second angle (β), wherein the second angle (β) is between 0° and 80°, preferably between 0° and 60°, comprising the following steps - emitting a transmission signal with a plurality of frequency ramps, - receiving one reception signal per frequency ramp of the transmission signal, - storing the reception signals, - performing a first spectral analysis of each individual reception signal, - performing a second spectral analysis of several reception signals or output signals of the first spectral analysis at at least one location of the signal, - determining a height (h) of the medium on the conveyor belt based on the output signals of the first spectral analysis, the method being characterized by the following steps: - determining a velocity (v) based on the output signals of the second spectral analysis, and - determining a volume flow of the medium based on the height (h) and the velocity (v). wherein the radar measuring device is arranged and oriented such that a main emission direction (H 1) of the radar measuring device includes with a direction of a surface normal of the conveyor belt a first angle (α), wherein the first angel (α) is greater than 0° and smaller than 90°, and includes with a transport direction of the conveyor belt a second angle (β), wherein the second angle (β) is between 0° and 80°, preferably between 0° and 60°, comprising the following steps - emitting a transmission signal with a plurality of frequency ramps, - receiving one reception signal per frequency ramp of the transmission signal, - storing the reception signals, - performing a first spectral analysis of each individual reception signal, - performing a second spectral analysis of several reception signals or output signals of the first spectral analysis at at least one location of the signal, - determining a height (h) of the medium on the conveyor belt based on the output signals of the first spectral analysis, - emitting a transmission signal with a plurality of frequency ramps, - receiving one reception signal per frequency ramp of the transmission signal, - storing the reception signals, - performing a first spectral analysis of each individual reception signal, - performing a second spectral analysis of several reception signals or output signals of the first spectral analysis at at least one location of the signal, - determining a height (h) of the medium on the conveyor belt based on the output signals of the first spectral analysis, the method being characterized by the following steps: - determining a velocity (v) based on the output signals of the second spectral analysis, and - determining a volume flow of the medium based on the height (h) and the velocity (v). - determining a velocity (v) based on the output signals of the second spectral analysis, and - determining a volume flow of the medium based on the height (h) and the velocity (v).