Motor Efficiency Calculator
Electric motor efficiency from input and output power.
Enter your values
ⓘ Live results
Results
- Input power
- 1564 W
- Output power
- 1118.6 W
- Motor efficiency
- 71.5%
- Power lost as heat
- 445.4 W
Quick answer
Efficiency = output power / input power x 100%.
eff = Pout/Pin x 100
How to use the Motor Efficiency Calculator
- 1Enter the motor's electrical supply voltage, current and power factor.
- 2Enter the rated mechanical output in horsepower.
- 3Read the calculated efficiency and heat losses.
Worked example
Using the values the calculator loads with:
Inputs
- Supply voltage230 V
- Current draw8 A
- Power factor0.85
- Rated output1.5 hp
Results
- Input power1564 W
- Output power1118.6 W
- Motor efficiency71.5%
- Power lost as heat445.4 W
Frequently asked questions
What is a typical motor efficiency?
Standard motors run 80-90% efficient; premium efficiency motors can exceed 95%.
Why does power factor matter here?
Input real power depends on power factor; ignoring it overstates the electrical input.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.