Abstract: An electromagnetic flowmeter for measuring the mean velocity of a fluid flowing through a duct is described. In one embodiment the electrodes are shaped to provide a uniform weighting function relating fluid velocity distribution over the duct cross section to flowmeter output voltage representative of mean velocity. Flowmeters are described in which using large insulated electrodes sensitivity is made independent of velocity profile by either ensuring that the applied magnetic field is uniform and the virtual current in the duct is two dimensional, or vice versa.