Fast, free solar-PV sizing
Click through three short steps and download a shareable report.
Solar System Sizing Calculator for Homes and Small Businesses
Quickly calculate the ideal solar PV system for your home, cabin, or business—anywhere in the world. This free tool helps you determine the correct inverter size, number of solar panels, and battery storage, all based on your energy needs and location.
Why Use This Tool?
- Works globally using trusted solar data
- Simple input, fast results
- Generates a clear, printable PDF report
- Perfect for installers and self-planners
How It Works
- Enter your location and average monthly electricity use
- Select your roof direction and battery preferences
- Download or share a professional system sizing report
Frequently Asked Questions
Is this tool accurate?
It uses satellite-based solar data and established design rules. While it's not a substitute for a full engineering design, it's highly useful for planning and comparison.
Do I need to register?
No registration is required. Your sizing report is created instantly and stored securely for a short period.
Can I share my report?
Yes — your report can be downloaded or shared via a private link. It’s a convenient way to discuss your system with installers or friends.
Does it work for off-grid systems?
Yes. The tool includes battery storage and autonomy options, making it suitable for both grid-tied and off-grid scenarios.
Start sizing
How the calculator works
- Irradiance data – We pull long-term solar-insolation figures from the EU PVGIS database for your coordinates.
- System losses – The model applies realistic losses (temperature, wiring, inverter efficiency, soiling).
- Load profile – Your daily or monthly kWh is converted to peak-sun-hour demand.
- Simulation – Tilt and azimuth are varied, then the worst-month output is matched to your desired autonomy hours.
- Output – You get system kWp, inverter kVA, battery kWh, expected annual yield, and a printable report you can send to suppliers.