Soffit Calculator
Calculate the total soffit area needed for your home's eaves, including material estimation for panels, vents, and trim.
Published by:
isCalculator Editorial Team
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How to use this tool?
How to Use the Soffit Calculator
This calculator estimates the total soffit area, panel material, ventilation, and trim needed for your eaves. All measurements must be in feet (imperial).
- Enter Eave Length and Width – Input the length and width of one eave side (in feet).
- Select Number of Sides – Choose 2, 3, or 4 sides (default is 4 for a rectangular house).
- Set Waste Factor – Add a percentage for material waste (default 10%).
- Optional: Panel Width – If you know the panel width (e.g., 0.5 ft for 6-inch panels), enter it to get linear footage of panels needed.
- Click "Calculate" – Results will show:
- Total Soffit Area (sq ft) – includes waste.
- Linear Footage of Panels – only if panel width was provided.
- Vents Recommended – based on 1/300 ventilation rule (each vent ~0.5 sq ft).
- Trim Length – total perimeter of all eaves (in feet).
Tip: Ensure all inputs are positive numbers. The waste factor must be between 0 and 100.
Previous Results
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Frequently Asked Questions
A soffit is the underside of an eave or roof overhang. It often includes vents for attic ventilation.
Measure the length and width of each eave side. Multiply to get area per side, then multiply by number of sides. Add waste factor for cuts.
Building codes typically recommend 1 square foot of vent area per 300 square feet of attic floor area. This calculator uses 1/300 of soffit area as a guideline.