Solar ROI Estimator
System size, savings & payback from your bill and roof area
Free · No sign-up · Computed instantly on your device
Your Details
Estimates assume ~4 units/kW/day generation, 80 sq.ft per kW, and a tariff of ₹8/unit. Net of PM Surya Ghar central subsidy (up to ₹78,000). Final sizing follows a free on-site survey.
Recommended system capacity
4.2kW
Covers ~100% of your current bill
Estimated monthly savings
₹4,000
₹48,000 per year
Payback period
4.8 yrs
Then ~22 years of near-free power
Indicative investment
₹2,29,167
Net of PM Surya Ghar central subsidy (up to ₹78,000).
CO₂ offset per year
5.2 t
≈ 234 trees planted
These are indicative estimates for education and planning. Actual sizing depends on a site survey, shadow analysis, and DISCOM sanction. Read the PM Surya Ghar guidelines or browse the vendor directory to take the next step.
About This Calculator
The Solar ROI Estimator answers the first question every rooftop journey starts with: what does solar actually save me? It sizes a system from two numbers you already know — your average monthly electricity bill and your usable roof area — and returns the recommended capacity in kW, projected monthly savings in rupees, the indicative investment, and the payback period in years.
The model uses typical Indian rooftop economics: ~4 units of generation per kW per day, 80 sq.ft of shadow-free roof per kW, and current residential and commercial tariff bands. Results are indicative — a proper site survey and shadow analysis refine the final design — but they are accurate enough to decide whether solar is worth pursuing and what budget range to expect.
Frequently Asked Questions
- How Accurate Is a Solar ROI Calculator?
- Within roughly ±15% for typical rooftops. The two biggest real-world variables are shading on the roof and your DISCOM tariff slab. Use the result to shortlist budget and system size, then validate with an on-site survey.
- Does the Estimate Include the PM Surya Ghar Subsidy?
- Yes — residential cost assumptions are net of the central subsidy (up to ₹78,000 on the first 3 kW). Commercial and society estimates use scale pricing without capital subsidy.