Siding Calculator
Calculate how many squares of siding you need for any wall. Enter wall dimensions, window and door counts, and get net area with waste factor.
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Squares of Siding (10% waste)
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Gross Wall Area —
Net Area (w/ deductions) —
Extended More scenarios, charts & detailed breakdown ▾
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Squares Needed
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Gross Wall Area —
Net Area —
Professional Full parameters & maximum detail ▾
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Area Breakdown
Gross Wall Area —
Gable End Area —
Net Siding Area —
Squares of Siding —
Accessories
Soffit/Fascia (linear ft) —
Corner Posts Needed —
Cost Estimate
Material Cost —
Labor Cost (est.) —
Total Project Cost —
How to Use This Calculator
- Enter the wall height and length in feet.
- Enter the number of windows and doors to deduct openings.
- Results show gross area, net area, and squares of siding needed.
Formula
Gross Wall Area = Height × Length
Deductions = (Windows × 15 sq ft) + (Doors × 20 sq ft)
Net Area = Gross − Deductions
Squares = ceil(Net Area × waste factor ÷ 100)
Example
Example: 9 ft wall × 40 ft long, 3 windows, 1 door → 360 − 45 − 20 = 295 sq ft net → 3.25 squares (with 10% waste: 3.6 squares).
Frequently Asked Questions
- One square of siding covers 100 square feet. Most siding products are sold and priced by the square.
- Standard window openings average 15 sq ft and door openings average 20 sq ft. This calculator uses those defaults when you enter the number of openings.
- Use 10% for simple rectangular walls. Add 5–10% more for complex walls with many angles, dormers, or diagonal cuts.
- A triangular gable end area = (base × height) ÷ 2. Use the Professional tab to add gable end area to your total.
- Vinyl siding is lighter and lower cost ($2–$7/sq ft installed). Fiber cement is more durable, fire-resistant, and costs $5–$12/sq ft installed.