Rooftop solar system cost estimate by kW (illustrative)

What this tool does. It multiplies the system size in kW by a low and a high price per kW and adds fixed extras, to give a rough range you can use to judge whether a quotation is in a sensible area. It is not a quote and the bands are illustrative assumptions, not published prices. Real prices vary by state, brand, roof type, height of the mounting structure, cable runs, season and the vendor's own costs.

Choosing a size. As a thumb rule, 1 kW of panels needs roughly 8–10 square metres (about 90–110 sq ft) of shade-free roof and produces on average around 3.5–4.5 units a day in much of India. Divide your average monthly units by about 120 to get a first estimate in kW. The sizing guide explains the full method.

Worked example (illustrative). A 3 kW on-grid system at ₹55,000–70,000 per kW plus ₹10,000 extras gives ₹1,75,000–2,20,000. Under PM Surya Ghar the CFA for 3 kW is ₹78,000, so the net cost would be about ₹97,000–1,42,000 before any state top-up.

Limits. Battery prices change quickly and depend heavily on capacity in kWh, not just kW. Since 22 September 2025 GST on solar power generating systems is 5%; check that the quotation shows GST separately.