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Fluid Mechanics Calculators

Flow Rate Calculator

Volumetric flow rate from pipe area and velocity (Q = A·v), in m³/s, L/min and gallons per minute.

Enter values

Results update as you type.

Result

Flow rate

176.71 L/min

Cubic metres per second
0.002945
Litres per second
2.945
US gallons per minute
46.68
Cubic metres per hour
10.603

About the Flow Rate Calculator

Volumetric flow rate from pipe area and velocity (Q = A·v), in m³/s, L/min and gallons per minute.

Also known as: volumetric flow rate, q = av, water flow rate, pipe flow rate, gpm calculator, water-flow-rate.

How to use this calculator

  1. Enter calculate from and the other fields.
  2. The result updates instantly as you type — press Calculate (or Enter) at any time.
  3. Review the breakdown shown under the main result.
  4. Use Copy result or Share to save the answer or send a link with your inputs.

Formula

Q = A × v = volume ÷ time

Worked example

Using the values pre-filled in the calculator above:

  • Calculate from: Pipe size and velocity
  • Pipe inside diameter = 50 mm
  • Fluid velocity = 1.5 m/s

the calculator returns:

  • Flow rate: 176.71 L/min
  • Cubic metres per second: 0.002945
  • Litres per second: 2.945
  • US gallons per minute: 46.68