About the Panel Requirements
The panel-requirement calculation converts a target system size — or your monthly electricity consumption — into a concrete module count, roof area, and orientation. It answers the most common first question: 'how many solar panels do I need?'
Formula
Panels = System size (Wp) ÷ Module wattage (Wp)
- System size
- Target capacity (Wp)
- Module wattage
- Rating of one panel, e.g. 550 Wp
From consumption: kWp = Annual kWh ÷ Yield (kWh/kWp/year)
- Annual kWh
- Your yearly consumption
- Yield
- State specific yield, ≈1,400–1,600 kWh/kWp/year
How to calculate it
- 1If sizing to your bill, convert annual consumption to the kWp needed using your state's specific yield.
- 2Divide the system Wp by the module wattage to get the panel count (round up).
- 3Multiply the panel count by the module area for roof footprint, adding a spacing allowance.
- 4Prefer a south-facing, shadow-free plane at your latitude tilt for maximum yield.
Worked example
A home using ~600 kWh/month (7,200 kWh/year) needs about 7,200 ÷ 1,500 ≈ 4.8 kWp. With 550 Wp modules that is about 9 panels over roughly 24 m² of shadow-free roof.
What you can calculate
- Panel count
- Roof area
- Orientation
- Space optimization
Standards & references
Frequently asked questions
How many solar panels do I need for my home?
As a rule of thumb, a 1 kW system is about 2 modern panels and offsets ~120–130 units/month in most of India. A typical home needs 3–5 kW (roughly 6–10 panels); size it to your monthly consumption and available shadow-free roof.
Is it better to have more panels or higher-wattage panels?
Higher-wattage panels reach the same kWp with fewer modules and less roof area, which is ideal when space is tight. The total kWp — not the panel count — determines generation, so match the kWp to your consumption first, then choose wattage to fit the roof.
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