Ridge Vent Calculator

Calculate ridge vent length and net free area for attic ventilation per IRC R806

Input Parameters

Results

--
Required NFA
sq in
--
Ridge Vent NFA
sq in
--
Soffit Vent NFA
sq in
--
Min Ridge Vent
ft

Reference

IRC R806: 1/150 ratio (no vapor barrier), 1/300 (with VB) NFA = Attic area × 144 / ratio 50/50 split between ridge and soffit