How Many Solar Panels Do I Need? Calculator
Find out how many solar panels you need to power your home. Enter your annual electricity use — or estimate it from your monthly bill — pick your region for local sun, and see the panel count, system size, roof area, and how much of your usage it offsets.
US home average ≈ 10,500 kWh/yr.
Panels needed
23 panels
- Annual production
- 12,089 kWh
- Usage offset
- 101%
- Roof area needed
- ≈ 484 sq ft
- Your annual use
- 12,000 kWh
Panels = (annual use × offset) ÷ (sun hours × 365 × derate), divided by panel wattage and rounded up. Roof area ≈ 19 W per sq ft. Actual count depends on your roof, shading, and orientation.
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Open calculatorSources & standards
This tool's methodology and data follow US standards and authoritative public datasets: