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Free Solar Panel Calculator

System size, output and savings for a rooftop solar array.

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Inputs

$

Result

System size needed

6.84 kW

Panels required18 × 400 W
Yearly generation8,994 kWh
Yearly bill savings$1,440.00

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Short answer

System size, output and savings for a rooftop solar array.

What is the Solar Panel Calculator?

System size, output and savings for a rooftop solar array.

How does the Solar Panel Calculator work?

Enter the inputs above and read the result.

Formula

kW = Daily kWh ÷ (Sun hours × 0.8)

Variables

  • 0.8System derate factor

Explanation

Real arrays lose roughly 20% to heat, wiring and inverter losses.

Examples

Applications

    Advantages

      Limitations

        Common mistakes

          Tips

            Related concepts

            The Solar Panel Calculator sits inside the Everyday & Utility Calculators hub, in the home & energy cluster. Utility usage and household running costs. Understanding the terms below makes the output easier to interpret and easier to compare against neighbouring measures.

            kilowatt-hourtariffstandby loadefficiency rating

            Practical use cases and industry applications

            Understanding Solar Panel

            System size, output and savings for a rooftop solar array. Within everyday & utility calculators, solar panel belongs to the home & energy cluster, where it shares terminology and assumptions with closely related tools.

            Learning how solar panel is calculated

            Real arrays lose roughly 20% to heat, wiring and inverter losses. Working through the variables one at a time — 0.8 — makes the result reproducible by hand and easier to sanity-check.

            Using solar panel to make a decision

            Because outputs depend on the assumptions you enter, run more than one scenario before committing to a figure.

            How solar panel compares with related measures

            kilowatt-hour, tariff, standby load, efficiency rating all describe adjacent aspects of home & energy. Comparing this calculator's output against those measures — using the related tools listed on this page — prevents a single metric from being read in isolation.

            Frequently asked questions

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