Soffit Vent Area
Calculator

Inputs

Net free vent area (m²)
0.666666

Results

Net free vent area (m²)
0.666666
Net free vent area (cm²)
6,666.666666

Construction results

Net free vent area (m²)0.666666
Net free vent area (cm²)6,666.666666

formula-map diagram

Net free vent area (m²)
0.666666
Net free vent area (cm²)
6,666.666666

Formula breakdown

Formula

net free area = attic floor area ÷ ratio denominator (typically 1/150)

= 0.66666666666667

Note

Simplified model: results are quantity estimates only. They ignore openings, overlaps, cuts, site conditions and local building codes. Structural figures are not a substitute for a design by a qualified engineer.

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