In physics and engineering, in particular fluid dynamics and hydrometry, the volumetric flow rate, is the volume of fluid which passes per unit time; usually represented by the symbol Q. The SI unit is m3/s. Another unit used is sccm (standard cubic centimeters per minute).
In US Customary Units and British Imperial Units, volumetric flow rate is often expressed as ft3/s (cubic feet per second) or gallons per minute (either U.S. or imperial definitions).
Volumetric flow rate should not be confused with volumetric flux, as defined by Darcy's law and represented by the symbol q, with units of m3/(m2•s), that is, m•s−1. The integration of a flux over an area gives the volumetric flow rate.