Soffit Calculator

Size the panels and ventilation under your eaves. Enter the house perimeter and eave width to get soffit panels and attic vent requirements.

ft
ft
sq ft
For vent sizing (1/300 rule).

🏠 Eave math

Perimeter times eave width gives the under-eave panel area.

🕹️ Vent balance

Splits the 1/300 attic vent requirement between soffit and ridge.

🔎 Panel count

Rounds up to whole panels with waste built in.

🔒 Private

All calculations run locally in your browser.

More exterior tools

Finish the eaves and beyond.

Siding Calculator → Roof Size Insulation

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