Vazão Hidráulica
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
Q = Av
About this calculator
The hydraulic flow rate calculator determines the volumetric flow rate (Q) of a fluid in motion using the equation Q = A × v, where A is the cross-sectional area of the conduit and v is the average fluid velocity. Flow rate represents the volume of fluid passing through a section per unit time, essential for pipe, channel, and hydraulic system design.
Operation is simple: enter the area (in square meters, square centimeters, or other units) and the velocity (in meters per second). The calculator automatically converts units to the International System and applies the formula, displaying the result in m³/s, L/s, or other flow units. The tool also allows calculating area or velocity if the other two values are known.
Use this calculator in situations such as pump sizing, irrigation systems, water supply networks, storm drainage, or any fluid transport project. For example, when designing a pipeline to supply a reservoir, flow rate determines the required pipe diameter to meet demand.
Important precautions: ensure area and velocity units are compatible (e.g., m² with m/s). The formula assumes uniform flow and incompressible fluid. In pipes with section changes or turbulence, velocity may vary, requiring average velocity. Additionally, actual flow rate may be lower due to head loss, friction, or obstructions.
Frequently asked questions
What is hydraulic flow rate and how is it calculated?
Hydraulic flow rate is the volume of fluid passing through a cross-section per unit time. It is calculated by multiplying the cross-sectional area by the average fluid velocity (Q = A × v).
What flow rate units does the calculator support?
The calculator supports units such as m³/s, L/s, L/min, m³/h, gallons per minute (GPM), and cubic feet per second (CFS). Just select the desired unit.
Can I use this calculator for gases?
Yes, as long as the gas is considered incompressible (low velocity and pressure variation). For compressible gases, the simple formula may not be accurate.
How do I convert flow rate from m³/s to L/s?
Multiply the value in m³/s by 1000 to get L/s. The calculator performs this conversion automatically.
Does the calculator account for friction losses?
No. The formula Q = A × v does not include losses. For actual flow rate, use equations like Darcy-Weisbach or Hazen-Williams, which consider head loss.