Power ConverterFree online other calculator — instant results, no sign-up
Convert standard power units.
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About the Power Converter
The Power Converter converts power values between watts, kilowatts, and mechanical horsepower. Select the starting and destination units to express the same power in a different unit. With the default settings, it converts 1 watt to 0.001341 mechanical horsepower.
- Value
- The power amount to convert, measured in the selected From unit and defaulting to 1.
- From
- The unit of the input power—watt, kilowatt, or mechanical horsepower—with watt selected by default.
- To
- The unit for the converted power—mechanical horsepower, kilowatt, or watt—with mechanical horsepower selected by default.
Formula and method
P_out = P_in × c_from / c_to, where c(watt) = 1, c(kilowatt) = 1000, and c(mechanical horsepower) ≈ 745.699872 watts per unit. For the default inputs: P_out = 1 × 1 / 745.699872 ≈ 0.001341 mechanical horsepower.
- P_inThe entered power value in the From unit.
- P_outThe converted power value in the To unit.
- c_fromThe number of watts per unit of the selected From unit.
- c_toThe number of watts per unit of the selected To unit.
Multiply the input value by its watts-per-unit factor to express the power in watts. Divide that watt value by the destination unit's watts-per-unit factor. For the default settings, dividing 1 watt by approximately 745.699872 watts per mechanical horsepower gives 0.001341 mechanical horsepower when rounded to six decimal places.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Value1
- Fromwatt
- Tomechanical horsepower
Results
- Result0.001341 mechanical horsepower
How to use the Power Converter
- 1Enter the power amount in Value; leave it at 1 to follow the default example.
- 2Select the starting unit under From; use watt for the default example.
- 3Select the destination unit under To; use mechanical horsepower for the default example.
- 4Read the converted result: with the default inputs, Result = 0.001341 mechanical horsepower.
Reading your result
The Result row shows the entered power expressed in the selected To unit. In the default example, 0.001341 mechanical horsepower represents the same power as 1 watt, subject to display rounding. The number changes because the unit changes, not because the physical power changes.
Limitations
This tool converts units only; it does not calculate equipment efficiency, electrical losses, or actual motor output. Mechanical horsepower is distinct from metric horsepower and boiler horsepower, which are not supported here. Rounded results may lose precision, especially for very small values. Power is a rate of energy transfer, so this calculator cannot convert watts directly to energy units such as kilowatt-hours without a duration.
Common questions
Which definition of horsepower does the Power Converter use?+
It uses mechanical horsepower, approximately 745.699872 watts per horsepower. It does not use metric horsepower or boiler horsepower.
Why does the default conversion show such a small horsepower value?+
A mechanical horsepower is much larger than a watt. Dividing the default 1 watt by approximately 745.699872 gives the displayed result of 0.001341 mechanical horsepower.
Can I use this conversion to find a motor's shaft horsepower from its electrical input watts?+
The converter can express electrical input power in mechanical horsepower units, but it cannot determine shaft output power. That requires the motor's efficiency or a measured output value.
Can this calculator convert kilowatts to kilowatt-hours?+
No. Kilowatts measure power, while kilowatt-hours measure energy. Calculating energy requires multiplying power in kilowatts by operating time in hours, assuming constant power.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
Further reading
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Results are estimates for informational purposes and are not financial, medical or legal advice.