Volumetric flow rate is the volume of fluid that passes through a certain face per unit time.

It can be expressed with the following equation:

Q = Av

where;
Q : Volumetric flow rate [m3/s]
A : Area of the face through which fluid passes [m2]
v : Average velocity of flow perpendicular to the face through which fluid passes [m/s]

It can also be called simply as flow rate.