Free tool
What size solar system do I need?
Enter your average monthly units or your bill. The calculator sizes a system so that a year of generation matches a year of consumption, then shows panels, roof area and the subsidy band.
Figures verified on 16 Sept 2026. Every number links to its source on the sources page.
kWh
Add up 12 bills and divide by 12; summer alone overstates it.
Recommended size
2.5 kW
- Consumption used
- 300 units a month
- Expected generation
- about 281 units a month
- Panels
- 5 × 540 Wp
- Roof needed
- 250–292 sq ft, shadow-free
- Subsidy note
- within the subsidised 3 kW band
Sizing matches annual consumption to annual generation at 113 units per kW per month (the published planning yield with a 10% derate). Your sanctioned load and roof shading decide the final size; an engineer confirms both on a free visit. Prices for this size: see the 3 kW page.
Questions people ask
Sources
- 1.Savings for commercial connection consumers of Noida by going solar — Verde Solaire, 4 May 2023
- 2.Savings for commercial connection consumers of Delhi by going solar — Verde Solaire, 4 May 2023
- 3.3 kW Solar Panel Price in Delhi (With Subsidy & Easy Loan – 2025 Guide) — Verde Solaire, 28 Jun 2025
- 4.DERC (Net Metering for Renewable Energy) (First Amendment) Regulations, 2024 — DERC (hosted by Tata Power-DDL), 26 Jul 2024
- 5.PM Surya Ghar: India's Solar Revolution (backgrounder) — PIB / MNRE, 13 Mar 2025