Estimate solar system size, panel count, annual energy production, roof area and market-based installation cost from monthly electricity use.
How the solar sizing works
The calculator starts with monthly electricity use and your desired solar coverage, then applies peak sun hours and a system-loss factor to estimate DC array size and panel count.
Before you buy equipment
This is a planning estimate. Shading, roof orientation and tilt, module temperature, inverter design, local weather, roof loading and electrical requirements can change the final system design.
Frequently asked questions
What are peak sun hours?
Peak sun hours express daily solar energy as equivalent hours at full reference irradiance; they are not simply daylight hours.
Is the panel count a final design?
No. It is a planning estimate that should be validated against shading, orientation, roof conditions, equipment choices and local electrical requirements.
What does Solar Panel Calculator & Cost Estimator calculate?
The calculator uses the measurements and values you enter and applies a defined deterministic formula. Change the inputs and the result is calculated again from those values.
Can I save this calculation to a project?
Yes. After calculating, use “Add to my project estimate” to save the result in your current Calcavera project estimate. You can repeat this with other calculators to build a multi-item project.
Can I print or save the estimate as a PDF?
Yes. Open the saved project estimate, then use the “Print / Save PDF” button. Your browser can print the estimate or save it as a PDF file.
Can I use metric and imperial units?
Yes. Where supported by the calculator, you can mix common metric and imperial input units. Calcavera converts measurements before running the calculation and shows the selected output unit.
Are the cost figures a contractor quote?
No. Cost ranges are planning estimates and appear only when an active market rate is available. Supplier pricing, labor, taxes, delivery, specifications and site conditions can change the final cost.