Attic CFM Calculator

Calculate attic ventilation airflow in cubic feet per minute.

Three-dimensional space occupied (L × W × H for boxes).
cu ft
Time measurement in hours.
Thermal measurement in specified units (°F, °C, or K).
F

Results

CFM Required:
Calculated cfm required based on your inputs.
-CFM
Total NFA Needed:
Sum of all calculated values.
-sq in
Ventilation Type:
Calculated ventilation type based on your inputs.
-
Reference: Industry Standards. ASHRAE attic ventilation guidelines.