The main differences between a venturimeter and orifice meter are:

i) The venturimeter can be used for measuring the flow rates of all incompressible flows; whereas orifice meters are generally used for measuring flow rates of liquids.

ii) Venturimeter is installed in pipeline only and flow continues through the pipeline. In orifice meter, the entire potential energy is converted to kinetic energy and jet discharges freely into open atmosphere.

iii) In venturimeter, the flow velocity is measured by noting the pressure difference between the inlet and throat of venturimeter, whereas in the orifice meter, the discharge velocity is measured by using pilot-tube or by trajectory method.