Fan Calculator

Created by Gabriela Diaz
Last updated: Aug 30, 2022

With this fan calculator, you can find the airflow of a fan in CFM in a breeze. By entering the power and pressure generated by the fan, you'll instantly get your fan flow rate in CFM. You could also use this tool to calculate fan power or pressure.

If you are a fan of fans or simply would like to learn more about them, then you might like to read the accompanying text to learn:

  • What a fan is;
  • How does a fan work;
  • How to calculate the CFM of a fan using the fan's power and pressure; and
  • The formula for air flow rate in CFM.


What is a fan?

Fans are devices used for moving air by means of the rotational motion of radial blades attached to a hub (impeller), usually driven by an electric motor.

Fans are everywhere and are a critical element in different processes. The airflow produced by them is mainly utilized for temperature regulation, as part of cooling systems, HVAC (heating, ventilation, and air conditioning), building ventilation, drying, and as part of boiler systems, among other applications.

Fans work similarly to compressors, meaning they both are devices that use a rotating impeller to increase the pressure of air or other gases. Air moving from one point to another is possible because of a pressure difference, going from the zone of higher pressure to the zone of lower pressure.

A fan generates air movement by creating these pressure differentials where the higher the pressure differential, the greater the quantity of air that will flow.

💡 The main difference between a fan and a compressor is the pressure ratio and air volume they can work with. Fans generate lower pressure increases and can work with greater air volume than compressors.

How to calculate the CFM of a fan

The airflow generated by fans is usually measured in terms of volume per unit of time. Typically, fans are specified in CFM (cubic feet per minute) to indicate the volume of air in cubic feet a fan can move in one minute.

This fan air flow rate can be measured using a device or estimated by relating the fan's electric power consumption and the pressure it creates. In general, we can represent the air flow rate of a fan as:

Air flow rate=PowerPressure\small \text{Air flow rate} = \cfrac{\text{Power}}{\text{Pressure}}

In the calculation of a fan air flow rate, we can express the result in any consistent flow rate unit, but if we want to get the value in CFM, we may need to make some conversions. The air flow rate formula in CFM is:

CFM=Power ×530Pressure2989\small \text{CFM} = \cfrac{\text{Power} \ \times 530 }{\cfrac{\text{Pressure}} {2989}}


  • CFM\text{CFM} — Air flow rate in cubic feet per minute.
  • Power\text{Power} — Refers to the electric power used by the fan expressed in horsepower. Here appears multiplied by 530, which is a conversion factor.
  • Pressure\text{Pressure} — Total pressure generated by the fan, expressed in pascals. We can convert a pressure measured in pascals to feet of water dividing by 2989.

To learn more about the conversion of these units, you can take a look at the power converter and the pressure converter 🧮

Using the fan calculator

Here's how to calculate a fan's air flow in CFM with this fan calculator:

  1. If you know how much power the fan consumes, enter it in the Power output box.

  2. If, on the other hand, this parameter is unknown, you can estimate it by using the calculator's Advanced mode. Here enter the fan's voltage, current, and efficiency, and the calculator will calculate the power output for you.

  3. Next, enter the Pressure value specified by the manufacturer.

  4. Finally, the calculator will display the CFM value.

🙋 Like all our calculators, the fan CFM calculator works in any direction. This means you could also use this tool to calculate fan power or it's pressure!

Gabriela Diaz
Power output
cu ft
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