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.

FAQ

What is CFM and why is it important for fans?
CFM stands for Cubic Feet per Minute and is a measure of the volume of air moved by a fan per minute. It’s important because it helps determine the fan’s efficiency and suitability for a specific space, ensuring adequate ventilation and air circulation.

How does pressure affect a fan’s CFM?
Pressure, measured in pascals, impacts a fan’s CFM by influencing the amount of force the fan needs to exert to move air. Higher pressure requires more power to achieve the same CFM, affecting the fan’s efficiency and performance.

Can I calculate CFM for a fan with less than 100% efficiency?
Yes, to calculate CFM for a fan with less than 100% efficiency, first calculate the theoretical CFM using the provided formula and then multiply the result by the fan’s efficiency rating. This accounts for real-world factors that reduce a fan’s performance.

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