Last updated: 21 June 2026
Rooftop Solar Calculator India
Turn your monthly electricity use into a practical rooftop solar size, generation, cost and savings estimate for your location.
Independent calculator — not a government website.
Central subsidy slabs
For eligible residential households under PM Surya Ghar.
Up to 1 kW
₹30,000
Up to 2 kW
₹60,000
3 kW or higher
₹78,000
maximum
No extra central subsidy beyond 3 kW.
How rooftop solar generation is estimated
Monthly generation is calculated as system size × state solar yield × 30 days. The state yield is deliberately editable and is only a planning average. Roof direction, tilt, shade, heat, dust and equipment losses all influence actual output.
Generation is not the same as bill reduction
The calculator limits savings to your estimated monthly electricity use. This avoids valuing more solar units than the household currently consumes at the full retail tariff. Fixed charges and export-credit rules can still reduce the actual bill benefit.
- Review daytime consumption and net-metering terms
- Do not assume every generated unit offsets every bill component
- Compare installer generation guarantees carefully
Cost assumptions to review
The starting cost is ₹60,000 per kW and can be edited. A complete quote should clearly separate modules, inverter, mounting structure, electrical protection, approvals, taxes, warranties and after-sales service.
Frequently asked questions
Clear answers, with the important caveats left in.
How much electricity can a 3 kW system generate per month?
At the India default of 4.2 units per kW per day, the estimate is about 378 units a month. State assumptions and the actual site can be higher or lower.
How much roof area does rooftop solar need?
This calculator uses about 100 sq ft per kW, including practical spacing. A 3 kW estimate therefore uses about 300 sq ft.
Does the calculator include battery cost?
No. It estimates a grid-connected rooftop system at a per-kW cost you can edit. Add battery, backup and financing costs separately when comparing quotes.
How accurate is this calculator?
It is a planning estimate based on the values you enter, a state-level solar-yield assumption and the published central subsidy slabs. Shade, roof direction, equipment performance, local tariff design and approval rules can materially change the real outcome.
Is this website official?
No. This is an independent calculator and is not affiliated with the Government of India, MNRE, PM Surya Ghar or any DISCOM. Verify eligibility and subsidy amounts on the official portal and with your DISCOM.
Get rooftop solar quotes
Leave your details for the future quote-matching service. This demo form does not send data anywhere yet.