Solar System Sizing Calculator
Enter bill, rate, sun hours and installed cost to estimate system size, panels, cost and simple payback.
From electricity use to target energy
The calculator multiplies annual use by target coverage. Annual use of 5,000 kWh and an 80% target correspond to 4,000 kWh of solar energy per year.
Specific yield and losses
Specific yield states how many kilowatt-hours one installed kWp is expected to produce annually. Use a local value for location, tilt, and orientation. The loss percentage is only a broad system allowance.
Panels and roof area
Calculated kWp is divided by panel rated power and rounded up. Displayed area is only panel count times panel area; setbacks, walkways, and roof obstructions require more space.
What professional design must add
Structure, shading, strings, inverter sizing, storage, self-consumption, grid connection, and local rules determine the real system. Cost and currency come only from your inputs.