Vortex shedding flowmeters measure the frequency of vortices shed from a blunt obstruction, called a "bluff body," placed in the pipe. As the flow divides to go around the bluff body, vortices are created on each side of the divided stream. The rate of vortex creation is proportional to the stream velocity. Since each vortex represents an area of low pressure, the presence-then-absence of low pressures is counted and the count is proportional to the velocity.

Vortex flowmeters provide good measurement accuracy with liquids, gases, or steam and are tolerant of fouling. They have high accuracy at low flow rates; the measurement is independent of material characteristics. They require long runs of straight pipe. Even though the accuracy of vortex meters is often stated as a percent of flow rate rather than of full scale which does indicate higher accuracies, below a certain flow rate they cannot measure at all. At some low flow rate the Reynolds number will be low enough so no vortices will be shed.