Solar Panel Size Calculator
Calculate the solar system size needed to cover your daily energy consumption.
Calculate
Enter your values below.
Result
Recommended system size
0
Formula used
System size (kW) = Daily energy need ÷ (Peak sun hours × Efficiency)
Example: 20 kWh/day need, 5 peak sun hours, 80% efficiency → system size = 5 kW.
How to use this calculator
- Enter Daily energy need (kWh), Peak sun hours per day, System efficiency (0-1).
- Press Calculate to see your result instantly.
FAQ
Frequently asked questions
What are 'peak sun hours'?
The equivalent number of hours per day the sun delivers maximum standard intensity — not the same as total daylight hours.
Why include a system efficiency factor?
Real systems lose some energy to inverter conversion, wiring, temperature, and panel degradation.
Where do I find peak sun hours for my area?
Solar irradiance maps and databases (often provided by government or solar industry sources) list this by region.
Does this account for seasonal variation?
No, use an average or your worst-case season's sun hours for a more conservative sizing.