Solar PV Calculator
Enter your daily energy consumption and local sun exposure to estimate the system size, panel count, and generation you'd need.
Solar PV Calculator
Results
- Required system size
- 2.50 kWp
- Panels needed
- 5
- Installed system size
- 2.75 kWp
- Estimated daily generation
- 11.0 kWh
- Estimated monthly generation
- 330 kWh
How to size a solar PV system
Enter your daily energy consumption and local sun exposure to estimate the system size, panel count, and generation you'd need.
How the system size is calculated
- Formula
system_kW = daily_kWh / (peak_sun_hours × efficiency)
What "peak sun hours" means
It's not daylight hours — it's the equivalent number of hours per day the sun would need to shine at its peak intensity (1000 W/m²) to deliver the same total energy your location actually receives. Typical values range from about 3–4 in cloudier northern regions to 5–6 in sunnier ones; check a solar irradiance map for your specific location.
How to use it
- Enter your average daily consumption in kWh.
- Enter peak sun hours for your location and your chosen panel's wattage.
- Adjust system efficiency to account for inverter and wiring losses.
Privacy
Runs locally in your browser. No data is sent to the server.
FAQ
What system efficiency should I use?
75–85% is a reasonable range for a typical grid-tied inverter system once wiring, temperature derating, and inverter conversion losses are accounted for.
Does this account for seasonal variation?
No — it uses a single average peak-sun-hours figure. Real generation is higher in summer and lower in winter; use a conservative (lower) figure if you want the estimate to hold up through winter months.
Can I use this instead of a professional design?
Use it for a ballpark estimate only. A real installation also depends on roof orientation, shading, local regulations, and your utility's interconnection rules — get a site assessment before buying equipment.