Attic Ventilation Calculator

Attic Ventilation Calculator

Calculate the required net free vent area (NFVA) for proper attic ventilation.

Attic Floor Area (sq ft)

Please enter a positive number.

Ventilation Ratio (e.g., 1:300 -> enter 300)

Please enter a positive integer.

Result

0 sq in

Formula: NFVA (sq in) = (Attic Area (sq ft) / Ratio) * 144