Solar Panel Calculator

Estimate how many solar panels you need based on energy usage, sun hours, and panel wattage.

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Monthly Usage (kWh)

Peak Sun Hours/Day

Panel Wattage (W)

System Efficiency %

Cost per Watt ($)

Electricity Rate ($/kWh)

📐 How We Calculate — Learn about our calculation methodology, data sources, and quality standards.

Frequently Asked Questions

What is the 30% ITC?

The Federal Investment Tax Credit (ITC) lets homeowners deduct 30% of solar installation costs from federal taxes through 2032. It steps down to 26% in 2033.

How much roof space do I need?

Each 400W panel occupies about 20 sq ft. A 20-panel system needs roughly 400 sq ft of unshaded south-facing roof.

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