CFM per Square Foot Calculator
Airflow intensity per square foot of floor area.
Enter your values
ⓘ Live results
Results
- CFM per sq ft
- 0.75
- Air changes per hour
- 5
- Total airflow
- 900 CFM
- Rating
- typical residential
Quick answer
CFM per square foot is total airflow divided by floor area, a quick sanity check on ventilation design.
CFM/sq ft = CFM / floor area
How to use the CFM per Square Foot Calculator
- 1Enter the total airflow the system delivers.
- 2Enter the floor area served and the ceiling height.
- 3Compare the rate with the band shown for that building type.
Worked example
Using the values the calculator loads with:
Inputs
- Total airflow900 CFM
- Floor area1200 sq ft
- Ceiling height9 ft
Results
- CFM per sq ft0.75
- Air changes per hour5
- Total airflow900 CFM
- Ratingtypical residential
Frequently asked questions
What is a normal residential rate?
Around 1 CFM per square foot is the classic rule of thumb for a cooling system.
Why include ceiling height?
Tall ceilings mean more volume per square foot, so the same CFM gives fewer air changes.
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.