Abstract: The invention relates to an apparatus for determining a flow rate, with at least one flow passage for a fluid, an adjustable measuring device and a throttle. The apparatus is characterized in that the throttle is arranged to be movable about at least one pivot axis and engages with a predetermined and variable flow edge section at least in a partial region of the fluid flow passage prior to the measuring device. The apparatus according to the invention further comprises a bypass, which is variable at least by means of a bypass actuating member.