Efficiency Calculator
Calculate the efficiency of a machine or process as a percentage by comparing useful energy output to total energy input.
Formula: η = (output / input) × 100
About Efficiency Calculator
Efficiency Calculator is a free online calculator that gives you an instant, accurate result as you type. Calculate the efficiency of a machine or process as a percentage by comparing useful energy output to total energy input.
The calculation uses the standard formula η = (output / input) × 100 and updates live with every change to the inputs. Everything runs client-side in your browser — fast, private, and free to use as often as you like.
No real machine reaches 100% efficiency: car engines convert only about 25-35% of fuel energy into motion, while electric motors can exceed 90%.
Frequently Asked Questions
Is Efficiency Calculator free to use?
Yes. Efficiency Calculator is completely free, with no sign-up, no downloads, and no usage limits. You can use it as many times as you like on any device with a web browser.
How accurate is this calculator?
The calculator applies the standard formula (η = (output / input) × 100) with full floating-point precision and rounds only the displayed result. For most practical purposes the results are exact.
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