Enter the total power delivered by the sun to the area of the solar panel and the total power generated by the solar panel to determine the solar panel’s efficiency.

Solar Panel Efficiency Formula

The following formula is used to calculate the efficiency of a solar panel:

E = Pout/Pin * 100 
  • Where E is the solar panel efficiency
  • Pout is the output power of the solar panel
  • Pin is the total power delivered by the sun to the area of the solar panel or cell

To calculate the solar panel efficiency, divide the power output by the power received by the sun, then multiply by 100.

Solar Panel Efficiency Definition

What is a solar panel efficiency?

Solar panel efficiency is the percentage of the total power delivered by the sun to the area of a solar panel that it can then convert into electrical power.

What is the average solar panel efficiency?

The average solar panel efficiency is between 12-16%.

Example Problem

How to calculate solar panel efficiency?

  1. First, determine the total power delivered to the area of the solar panel.

    For this example, we will use a simple value of 400 watts.

  2. Next, determine the total power output by the solar panel.

    In this case, the solar panel is able to generate 30 watts of power from the 400 watts of power delivered by the sun.

  3. Finally, calculate the efficiency of the solar panel.

    Using the formula above, the solar panel efficiency is calculated to be:
    E = Pout/Pin * 100
    E = 30/400 * 100
    E = 7.5%


What factors can affect the efficiency of a solar panel?

Several factors can affect solar panel efficiency, including the type of solar cells used, the angle and orientation of the panel, shading, temperature, and the cleanliness of the solar panels. High temperatures can reduce efficiency, while optimal angling towards the sun can increase it.

How can I improve the efficiency of my solar panel system?

Improving solar panel efficiency can be achieved by ensuring the panels are correctly angled towards the sun, keeping them clean to avoid shading from dirt or debris, using quality materials and technology, and incorporating solar trackers that follow the sun’s movement to maximize sunlight exposure.

Why is solar panel efficiency important?

Solar panel efficiency is crucial because it determines how much of the sunlight can be converted into usable electricity. Higher efficiency means more energy production from the same amount of sunlight, making the solar system more cost-effective and reducing the space needed for the installation of solar panels.