Power and Efficiency Calculator
Compare input energy with useful output over the same time. Find average input/output power, energy loss and conversion efficiency.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Divide energy transfer by elapsed time for average power. Divide useful output by input for efficiency. The energy difference is the loss from the chosen useful-output category.
P=E/t; efficiency=Euseful/Ein×100%; loss=Ein−Euseful
Worked example
1000J input and800J useful output over10s give100W input power,80W useful power,80% efficiency and200J loss.
Assumptions and input details
Input energy and elapsed time must be positive; useful output must lie between zero and input. Entered base quantities are capped at1e12. Compare the same time interval and a consistent system boundary. This is useful-energy efficiency, not a heat-pump coefficient of performance. Loss means energy outside the chosen useful output, not destroyed energy.
References: OpenStax average power
Unit definitions
Unit selection is independent of language. Each selector contains only units for its physical quantity. Calculations use defined base units internally.
SI prefixes are explicit: for example, milli means one thousandth, micro one millionth and kilo one thousand. Changing a unit changes the interpretation of the entered number.
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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