What size solar system do I need for my home?

Divide your monthly electricity units by about 120 (a 1 kW system generates roughly 4 units a day, about 120 a month). A home using 300 units a month typically needs around 2.5 to 3 kW. You also need about 100 sq ft of shade-free roof per kW.

What is the PM Surya Ghar subsidy in 2026?

The central subsidy is ₹30,000 per kW for the first 2 kW and ₹18,000 for the third kW, capped at ₹78,000 for systems of 3 kW or more. Some states add their own top-up. There is no extra central subsidy above 3 kW.

How much does rooftop solar cost in India?

Roughly ₹55,000 to ₹65,000 per kW before subsidy in 2026, so a 3 kW system is about ₹1.7–2.0 lakh, or around ₹1–1.2 lakh after the ₹78,000 subsidy. Payback is usually 3 to 5 years.

Solar Rooftop Calculator (India 2026)

Solar Rooftop Calculator

Size a rooftop solar system from your electricity bill and see the cost, the PM Surya Ghar subsidy, your monthly savings and the payback. Built on 2026 Indian rates — every assumption is editable to match your quote and state.

How it's calculated

Your bill divided by the tariff gives monthly units. A 1 kW system generates about four units a day, so the size needed is your daily use divided by that. Roof area is about 100 sq ft per kW. The central subsidy is applied in slabs — ₹30,000 per kW for the first 2 kW and ₹18,000 for the third — capped at ₹78,000 for 3 kW and above, plus any state top-up you enter. Payback is the net cost divided by yearly savings.

Subsidy caps at 3 kW; larger systems get no extra central subsidy. Savings assume net metering. Figures are indicative — confirm with an MNRE-empanelled vendor.

Frequently asked questions

Why is 3 kW the "sweet spot"?

The ₹78,000 subsidy maxes out at 3 kW, and 3 kW roughly covers the 300 free units the scheme targets for a typical home.

Do I need net metering?

Yes — it credits surplus daytime generation against night use, which is what makes the savings work.

Is the subsidy on my quote or a benchmark?

It's calculated on MNRE benchmark costs, so a higher vendor quote doesn't increase the subsidy.

Solar Rooftop Calculator

Your usage

Assumptions editable

How it's calculated

Frequently asked questions