Do you need to calculate the CFM of your exhaust fan? The Exhaust Fan CFM Calculator is here to assist you. By entering values such as room dimensions and air changes per hour, you can quickly find the required CFM for your fan.
What is Exhaust Fan CFM?
CFM stands for Cubic Feet per Minute. It measures the volume of air an exhaust fan can move in a minute. Calculating the CFM helps ensure proper ventilation and air quality in a space.
How to Use the Calculator
Enter Room Dimensions:
 Length (in feet)
 Width (in feet)
 Height (in feet)
Enter Desired Air Changes per Hour (ACH):
Input these values into the calculator to find the CFM.
Formula
The formula to calculate CFM for an exhaust fan is:
$\text{CFM} = \frac{\text{Room Volume (ft³)} \times \text{ACH}}{60}$
$\text{CFM} = \frac{\text{Room Volume (ft³)} \times \text{ACH}}{60$
Variable 
Description 
Length 
Length of the room in feet 
Width 
Width of the room in feet 
Height 
Height of the room in feet 
ACH 
Air Changes per Hour 
CFM 
Cubic Feet per Minute 
How To Calculate Exhaust Fan CFM
Example 1
Input:
 Length = 10 ft,
 Width = 12 ft,
 Height = 8 ft,
 ACH = 6
Calculation:

 Room Volume = Length × Width × Height = 10 × 12 × 8 = 960 ft³
 CFM = (960 × 6) / 60
 CFM = 96
Result: 96 CFM
Example 2
Input:
 Length = 15 ft
 , Width = 10 ft,
 Height = 9 ft,
 ACH = 8
Calculation:

 Room Volume = Length × Width × Height = 15 × 10 × 9 = 1350 ft³
 CFM = (1350 × 8) / 60
 CFM = 180
Result: 180 CFM
I hope you find the Exhaust Fan CFM Calculator useful. How was your experience? If you encounter any issues, please report them on our “Report an Error” page.