Enter the work output and the total heat input of a heat engine into the calculator to determine the thermal efficiency.

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## Thermal Efficiency Formula

The following formula is used to calculate the thermal efficiency.

ηth = W / Q

- Where
is the thermal efficiency*η*_{th} - W is the work output (J)
- Q is the heat input (J)

To calculate the thermal efficiency, divide the system work output by the heat input.

## Thermal Efficiency Definition

Thermal efficiency is the ratio of the work output to the heat input of a heat engine. In other words, the efficiency at which the engine converts heat to mechanical work.

## Thermal Efficiency Example

How to calculate thermal efficiency?

**First, determine the input heat.**Measure the total heat put into the engine. For this example, we will say this is 10 J of heat.

**Next, determine the workout output.**Measure the total work produced by the engine. For this example, the work is 9 J.

**Finally, calculate the thermal efficiency.**Using the formula we find the thermal efficiency to be 9/10 = .90 = 90%

## FAQ

**What is thermal efficiency?**

Thermal efficiency is the rate or efficiency at which a heat engine converts heat to work.

**Can something be 100% thermal efficient?**

No, in reality, heat engines will always have some losses associated with them.