Engineering
Basic

Efficiency

Ratio of useful output to input power.

Formula

η=PoutPin×100\eta = \frac{P_{out}}{P_{in}}\times 100

Variables

P_{out}Output
P_{in}Input

Example

80 W out of 100 W = 80%

Did You Know?

No real machine is 100% efficient, because friction and heat always skim off part of the input energy.

performance