Solar panel roof area
Enter your target system power, module efficiency, and a spacing margin. See the net and gross roof area you need.
Formulaarea (m²) = target watts / (1000 × efficiency)
Your inputs
Efficiency presets:
Net area
15.0 m²
200 W/m²
Gross area
17.3 m²
+15% spacing
Modules estimate
8
~400W per module
Methodology and assumptions
A typical c-Si panel produces roughly 1 kW/m² at nameplate efficiency; at 20% efficiency that is ~200 W/m². The spacing margin accounts for row gaps, cabling and ventilation — 10-15% for pitched roofs, up to 30-40% for ground-mounted trackers.
Our default is 200 W/m² for mid-range panels; adjust efficiency for your actual modules. The area is HORIZONTAL — for pitched roofs, check rafter dimensions and south exposure.
Other solar calculators
Solar system sizingHow many panel watts you need for your daily consumption.Battery capacityTick your appliances and get the Wh capacity you need.Savings and paybackHow much you save per year and how long the investment takes to pay off.Battery charge timeHow many hours to recharge a battery from your panels.