Flow Rate Calculator

This ultra calculator is special by allowing you to choose among a great variety of units (6 for diameter and 24 each for velocity and flow rate). Unlike other calculators, you are NOT confined to inputting diameter in inches, velocity in miles per hour, etc. making this calculator quite versatile.

1. Choose a property to be found

2. Enter known factors and choose units


Unit for result


Unit for result

Flow rate

Unit for result


To use this calculator you will need to:

  1. Choose the property you with to be found.

    • Diameter

    • Velocity

    • Flow rate

  2. Fill in the 2 values that you do know.

  3. Select the units of each value as well as the unit you would like the result displayed in.

  4. Click on CALCULATE