Enter the power output and pressure of your fan to calculate the CFM (cubic feet per min). The CFM is the volume per minute of air or fluid a fan is pushing.

Fan CFM Formula

The following formula can be used to calculate the volumetric flow rate of air by a fan. This formula assumes an efficiency of 100%.

CFM = P*2122/p
  • Where CFM is the cubic feet per minute
  • P is the power output (Watts)
  • p is the pressure (pascals)

To calculate the fan CFM, multiply the power output by 2122, then divide by the pressure.

In reality, the flow rate of a fan will vary based on the size, shape, and performance of the motors. No fan will ever reach 100% efficiency, but this calculator assumes as much for simplifying the equation. To calculate the results of a real fan, simply multiply the result by the efficiency.

fan calculator