5 Ways To Calculate Cfm For Bathroom Fan

For instance, if your bathroom is 75 square feet (7. 0 m2), choose a bathroom fan with at least 75 CFM.

For instance, if your bathroom is 60 square feet (5. 6 m2) and your ceiling is 10 feet (3. 0 m) tall, multiply them together to get 600. Divide 600 by 60 to get 10. Then multiply 10 by 8 to get 80 as the ideal CFM for your fan.

50 CFM for each toilet 50 CFM for the shower 50 CFM for a bathtub 100 CFM for a jetted tub

For instance, if you have an exhaust fan with a CFM of 50, then it moves 50 cubic feet of air each minute.

You want a fan strong enough to pull all of the air out of your bathroom every 7½ minutes to keep moisture from building up.

This is a great option for a small half-bath or a hallway bathroom.