A semi-empirical (dimensional) model has been developed to predict the performance of an inline dynamic mixer within a specific application to ensure effective process design and operation. Inline dynamic mixers (or rotor-stator mixers) are known to behave like centrifugal pumps, particularly when operating at high rotor speeds. A mismatch between the process flowrate and the mixer's inherent pumping action can result in either high or low pressure at the inlet of the rotor-stator mixer, which can influence process control. Experiments were conducted at pilot scale using three models of inline dynamic mixers from Silverson Machines Ltd., with water as the process fluid. A wide range of flowrates and rotor speeds were covered where the pressures at the inlet and outlet of the Silverson were measured in each condition. A good correlation (R-2 = 0.9998) between Silverson inlet pressure, process flowrate and rotor tip speed has been established but the expression requires knowledge of the nominal flowrate of the mixer model at a benchmark rotor tip speed. This reported model can serve as design criteria when selecting mixer models even at production scale. Crown Copyright (C) 2018 Published by Elsevier B.V. on behalf of Institution of Chemical Engineers. All rights reserved.