A novel method for estimation of unsteady flow rate using pressure at two or three points along a pipeline is described in this paper. The pressure data are processed using a wave propagation model to determine the unsteady flow. The comparison and analysis of two-transducer and three-transducer techniques are investigated through simulation. The proposed method is shown to be effective for unsteady flow rate measurement over a high bandwidth. However, if the pressure values from two transducers are used, inaccuracies exist at certain frequencies when the transducer spacing coincides with multiples of half a wavelength. The accuracy can be improved by adding a third transducer with unequal spacing. The three-transducer method has been implemented in experiments and has been found to be robust and reliable.