Plan your rooftop solar
Solar System Size Calculator
Estimate solar capacity, annual generation, roof space, and nearby common system sizes from your electricity use or monthly bill.
Smart result
Your solar size estimate will appear here
Start with your monthly bill or exact electricity units. We will explain the answer step by step.
Understand the calculation
Solar size is based on annual electricity demand divided by estimated annual generation from each kW after system losses. kW describes system capacity; kWh describes energy produced or consumed over time.
Results are planning estimates, not engineering designs, quotations, eligibility decisions, or guaranteed financial returns.
Frequently asked questions
How many kW of solar do I need?+
Divide annual electricity use by expected annual generation per kW after losses. The result is a planning estimate that needs a site assessment.
Can solar eliminate my entire electricity bill?+
Not necessarily. Fixed charges, export rules, seasonal variation, shading, and the timing of consumption can leave a remaining bill.
How much roof area is required?+
This calculator shows a configurable area range per kW. Panel dimensions, walkways, tilt, obstacles, and setbacks change the final requirement.
Does location affect output?+
Yes. Solar resource, weather, tilt, orientation, temperature, and shading affect generation. Current results use a general India estimate, not city-level data.