Solar System Size Calculator
Estimate the solar panel system you need based on your actual appliance usage
// Peak Sun Hours
The average hours per day your location receives strong enough sunlight for panels to produce at rated capacity. Varies by location: 3–4 hrs (UK/northern), 4–5 hrs (mid-latitudes), 5–7 hrs (sunny regions like South Africa, Australia, southern US).
// System Efficiency
Real-world panels don't produce 100% of their rated output. Losses come from heat, wiring, inverter conversion, shading, and panel degradation. 75–85% is typical. Use 80% as a safe default.
// Offset Target
100% means you want solar to cover all your usage. Set higher (e.g. 110–120%) to account for seasonal variation or future usage growth. Set lower if you only want solar to supplement grid power.
// Panel Size
Modern residential panels are typically 370–420W. Each panel is roughly 1.7m² (18 sq ft). Commercial panels can be larger. Adjust the panel wattage to match the panels available from your installer.
// How to Use Online Solar System Size Calculator
- Enter or paste your source data into the tool input.
- Click the primary action button to run Online Solar System Size Calculator.
- Review the output, then copy or export your result.
// FAQ: What does Online Solar System Size Calculator do?
Online Solar System Size Calculator helps you estimate the solar panel system you need based on your actual appliance usage in your browser with instant results.
// FAQ: How do I use Online Solar System Size Calculator?
Paste or type your input, choose the needed action, and copy the generated output when the result is ready.
// FAQ: Is my data safe when using Online Solar System Size Calculator?
Yes. Processing runs in your browser session for this page, so your content is not uploaded by this tool workflow.
// FAQ: Can I use Online Solar System Size Calculator on mobile devices?
Yes. Online Solar System Size Calculator works on modern mobile browsers, so you can run it from phones and tablets.