CFM per Watt Calculator
Airflow efficiency of a fan in CFM delivered per watt consumed.
Enter your values
ⓘ Live results
Results
- Efficiency
- 6.67 CFM/W
- Rating
- Good
- Power for 1000 CFM at this efficiency
- 150 W
Quick answer
CFM per watt equals the fan's airflow divided by its measured or rated electrical power draw.
CFM/W = CFM / Watts
How to use the CFM per Watt Calculator
- 1Enter the fan's rated or measured airflow.
- 2Enter its electrical power draw in watts.
- 3Compare the resulting CFM per watt against other models — higher is more efficient.
Worked example
Using the values the calculator loads with:
Inputs
- Airflow400 CFM
- Power draw60 W
Results
- Efficiency6.67 CFM/W
- RatingGood
- Power for 1000 CFM at this efficiency150 W
Frequently asked questions
What is a good CFM/W value?
PSC motor fans often run 3-6 CFM/W, while efficient ECM/EC fans commonly exceed 8-12 CFM/W.
Does this account for static pressure?
No — always compare fans at the same operating static pressure, since CFM/W drops sharply as pressure rises.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.