Solar Panel Calculator: Estimate Your Solar Energy Potential
Solar energy adoption is accelerating rapidly in India, driven by falling panel costs, rising electricity tariffs, and government subsidies. Installing rooftop solar panels can dramatically reduce or even eliminate your electricity bills while contributing to a cleaner environment. Our Solar Panel Calculator helps you estimate the system size you need, the expected energy generation, the installation cost, and your return on investment.
How Solar Panels Work
Photovoltaic (PV) solar panels convert sunlight directly into electricity. Each panel contains silicon solar cells that release electrons when struck by photons. These electrons flow as direct current (DC), which is converted to alternating current (AC) by an inverter for household use. Excess electricity generated beyond your consumption can be fed back to the grid through net metering, effectively making your electricity meter run backward.
Solar Irradiation in India
India receives 4–7 kWh/m²/day of solar irradiation, making it one of the best countries in the world for solar energy. Rajasthan, Gujarat, and parts of Maharashtra and Andhra Pradesh receive the highest irradiation (5.5–7 kWh/m²/day). Northern and eastern states receive somewhat less. Coastal areas can have intermittent cloud cover. Your location's peak sun hours directly determine how much electricity your system will generate.
System Size Calculation
Step 1: Calculate your average monthly electricity consumption in kWh (from your electricity bill).
Step 2: Determine daily consumption: monthly kWh ÷ 30.
Step 3: System size (kW) = Daily consumption (kWh) ÷ Peak sun hours for your location × System efficiency factor (0.75–0.85 to account for inverter losses, temperature effects, soiling).
Example: 300 kWh/month consumption, located in Mumbai (5 peak sun hours/day).
Daily consumption = 300/30 = 10 kWh. System size = 10 ÷ 5 ÷ 0.80 = 2.5 kW system needed.
Cost and ROI in India
Installed cost: approximately ₹40,000–₹60,000 per kW for a quality on-grid system (including panels, inverter, mounting, wiring, and installation). A 2.5 kW system: approximately ₹1,00,000–₹1,50,000.
PM Surya Ghar Scheme (Government Subsidy): Up to ₹78,000 subsidy for residential rooftop solar systems up to 3 kW (as of 2024). Check the current subsidy on the official PM Surya Ghar portal for updated amounts.
After subsidy: net cost may be ₹50,000–₹70,000 for a 2.5 kW system. At ₹8/unit savings and 300 units/month generated: ₹2,400/month savings → payback period approximately 2–3 years. System lifespan: 25+ years → 22+ years of free electricity after payback.
How to Use This Calculator
- Enter your average monthly electricity consumption.
- Enter your location (for peak sun hours) or enter hours directly.
- Enter local electricity tariff.
- Click Calculate for system size, estimated generation, cost, subsidy, and payback period.
Conclusion
Solar energy is one of the best long-term financial investments available to Indian homeowners, combining guaranteed electricity savings, government subsidies, and a 25-year asset life. Use our Solar Panel Calculator to size your system accurately, compare with installer quotes, and make a well-informed decision about going solar.