# Efficiency Calculator

Created by Luciano Mino
Last updated: Jul 23, 2022

Our efficiency calculator will help you instantly calculate the ratio of energy output to energy input.

We paired this tool with a short text covering:

• Efficiency definition;
• How to calculate efficiency;
• The efficiency formula; and
• Some use cases for efficiency.

## What is efficiency?

Efficiency is the ratio between the energy output of a machine or process and its energy input.

A machine converts only a certain amount of energy into useful work when you supply energy to it. The rest is lost as heat or friction.

💡 The Carnot efficiency is the efficiency of a machine working under the Carnot cycle, a thermodynamic cycle that maximizes the efficiency of a heat engine.

## How to calculate efficiency ― Efficiency formula

As we said, efficiency is the ratio between energy output and energy input. We summarize this in the efficiency formula:

$\eta = \frac{E_{out}}{E_{in}} \times 100 \%$

The result is a percentage between 0% and 100%, where 0% efficiency means all energy is lost during the process. On the other hand, no energy loss occurs in a 100% efficiency process.

In practice, the efficiency of any process cannot be 100%. There will always be energy losses.

🔎 Check our power dissipation calculator to learn why the components in an electric circuit heat as current flows through them.

## Efficiency use-cases

Although this efficiency calculator finds the energy efficiency of a process or machine, we can also use the efficiency definition to measure productivity or fuel efficiency.

For example, we measure the efficiency of a light bulb in lumens per watt by dividing the amount of light produced in lumens (the output) by the wattage consumption (the input).

A solar panel's efficiency is usually between 15-20%, and it tells us how much solar energy it can convert to usable energy.

Luciano Mino
Energy input
J
Energy output
J
Efficiency
%
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