A method and device for determining the flow rate of a flowing medium according to the plummet principle is characterized by a simplified determination of the calibration data sets in that at least one set of calibration data is recorded with at least one reference medium under at least one reference measurement condition. Then, a position of a plummet which is dependent on the flowing medium is determined under a measurement condition which differs from the reference condition. Here, the set of calibration data is converted from the reference measurement condition to the measurement condition, and from a determined position of the plummet, a measure for the flow rate of the medium is then determined.