# Efficiency Calculator

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.

Keep reading to learn more about this topic!

## 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:

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.