Enter the cross-sectional area and the fluid velocity into the calculator to determine the discharge rate.

Discharge Formula

The following formula is used to calculate a discharge rate.

Q = V * A
  • Where Q is the discharge rate
  • V is the velocity of the fluid
  • A is the area of the opening the fluid is moving through

To calculate total discharge, multiply the velocity of the fluid by the area of the opening.

Discharge Definition

A discharge is defined as the total rate of fluid moving through an opening, or discharging from that opening.

Discharge Example

How to calculate discharge?

  1. First, determine the velocity.

    Measure the velocity of the fluid. For this example, we will say the velocity is 20 m/s.

  2. Next, determine the area.

    Calculate the cross-sectional area the fluid is moving through. We will say this is 20 m^2 for this example.

  3. Finally, calculate the discharge.

    Using the formula we find the discharge rate to be 20*20 = 400 m^3/s.


What is a discharge?

Discharge is most often used to describe the volumetric flow rate of a fluid through an opening. In other words, how much of fluid is moving through an area every second.