Volume flow rate, often simply referred to as flow rate, is a measurement of the volume of fluid (liquid or gas) that passes through a given cross-sectional area over a specified period of time. It is typically denoted by the symbol  Q  and is measured in units such as cubic meters per second (m³/s), liters per minute (L/min ), or cubic feet per second ( ft3/s ).

Mathematically, volume flow rate ( Q ) is calculated as:

 Q = A x v 

Where:

•  Q = Volume flow rate (volume per unit time)
• A = Cross-sectional area through which the fluid is flowing
•  v = Velocity of the fluid

In many practical scenarios, especially with constant density fluids, volume flow rate can be determined by multiplying the cross-sectional area of the conduit (such as a pipe) by the average velocity of the fluid through that conduit.

Volume flow rate is a crucial parameter in various engineering, industrial, and environmental applications, including fluid dynamics, hydraulics, HVAC systems, chemical processing, and water management. It helps in designing systems, assessing performance, and ensuring efficient operation of fluid handling processes.