Chicken Coop Ventilation Calculator
Vent area and fan CFM for a coop.
Enter your values
ⓘ Live results
Results
- Passive vent area
- 4.8 sq ft
- Summer fan airflow
- 40 CFM
- Winter minimum
- 8 CFM
- Air changes at summer rate
- 8.3
- Floor space check
- 6 sq ft per bird
Quick answer
A coop needs roughly 1 square foot of vent opening per 10 square feet of floor, and 3-5 CFM of fan per bird in summer.
vent area = floor area / 10; summer CFM = birds x 5
How to use the Chicken Coop Ventilation Calculator
- 1Measure the coop floor and count the birds.
- 2Put vents high, above roost level, so there is no draft on the birds.
- 3Add a small fan for summer heat — ammonia and moisture build fast in still air.
Worked example
Using the values the calculator loads with:
Inputs
- Coop floor area48 sq ft
- Number of birds8
- Average height6 ft
Results
- Passive vent area4.8 sq ft
- Summer fan airflow40 CFM
- Winter minimum8 CFM
- Air changes at summer rate8.3
- Floor space check6 sq ft per bird
Frequently asked questions
Won't ventilation make them cold?
Chickens tolerate cold well but not damp; moisture causes frostbite, so keep vents open year-round.
Where should vents go?
High on opposite walls under the roof overhang, never at roost height.
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.