Enter the pump RPM and the pump displacement (in^3/revolution) into the RPM to Flow Rate Calculator. The calculator will evaluate the RPM to Flow Rate. 

RPM to Flow Rate Formula

The following two example problems outline the steps and information needed to calculate the RPM to Flow Rate.

FR = RPM * D / 231
  • Where FR is the RPM to Flow Rate (GPM)
  • RPM is the pump RPM 
  • D is the pump displacement (in^3/revolution) 

To calculate a flow rate from RPM, multiply the RPM by the displacement, then divide by 231.

How to Calculate RPM to Flow Rate?

The following example problems outline how to calculate RPM to Flow Rate.

Example Problem #1:

  1. First, determine the pump RPM.
    • The pump RPM is given as: 400.
  2. Next, determine the pump displacement (in^3/revolution).
    • The pump displacement (in^3/revolution) is provided as: 2.5.
  3. Finally, calculate the RPM to Flow Rate using the equation above: 

FR = RPM * D / 231

The values provided above are inserted into the equation below and computed.

FR = 400 * 2.5 / 231 = 4.239 (GPM)

Example Problem #2: 

For this problem, the variables required are provided below:

pump RPM = 600

pump displacement (in^3/revolution) = 3

Test your knowledge using the equation and check your answer with the calculator..

FR = RPM * D / 231 = ?