Roof Ventilation Calculator
Calculate proper ventilation requirements for your attic
How to use this calculator
The Master Roofer here—follow these steps to get a solid estimate:
- Enter your attic floor area in square feet.
- Select climate: cold, moderate, or hot.
- Click Calculate to see intake, exhaust, and total ventilation needed.
Aim for 50% intake (soffit) and 50% exhaust (ridge/roof vents) for balanced airflow.
Building Code Standard: 1 sq ft of ventilation per 150 sq ft of attic space (minimum)
Balanced System: 50% intake (soffit vents) and 50% exhaust (ridge/roof vents)