Solar Panel Wattage Calculator

A solar panel's wattage is its efficiency times its area and the sun's power.

How the Math Works

The Solar Panel Wattage Calculator uses the fundamental equation: watts equals efficiency times area times irradiance, divided by 100. This formula calculates the electrical power output of a solar panel by multiplying its conversion efficiency (expressed as a percentage), the surface area available for energy capture in square meters, and the solar irradiance value representing sunlight intensity in watts per square meter. Dividing by 100 converts the efficiency from percentage to decimal form, yielding the panel's rated electrical output in watts.

Practical Applications

To use this calculator practically, first determine your solar panel's efficiency rating from manufacturer specifications, measure the panel's surface area in square meters, and obtain the local solar irradiance value for your geographic location and installation date. Input these three values into the calculator to instantly determine your panel's rated wattage output under standard test conditions. This calculation helps you size your solar energy system correctly by knowing exactly how much power each panel can generate.

Day-to-Day Use

Understanding your solar panel's wattage rating helps you make informed decisions about your home's energy needs and solar investment. By calculating panel output, you can estimate your monthly electricity bill savings, determine how many panels you need for your energy consumption, and evaluate whether solar power is financially viable for your situation. This knowledge empowers you to reduce your carbon footprint while potentially saving thousands on electricity costs over time.

Worked example

A 20% efficient 1.6 m^2 panel under standard sunlight produces 320 W.

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