Enter a horsepower or kilowatt rating, select its horsepower definition, and convert it to the matching power unit.
Advanced options
Table of contents
How to use our Horsepower to kW Converter
- Choose "Horsepower to kilowatts" when your source shows hp, or choose "Kilowatts to horsepower" when it shows kW.
- Select "Horsepower type" that matches the source. Choose "Metric hp (PS or CV)" for ratings marked PS or CV.
- Choose "Motor nameplate" only when you copied the rating from a motor label; this changes the explanation, not the conversion.
- Enter the power value from the document or label, then select "Calculate".
- Check "Applied kW per horsepower" before using the answer: 0.7457 is mechanical hp, 0.746 is electric hp, and 0.735499 is metric hp.
Definitions
Horsepower (hp): A unit used to state power. Its kW equivalent depends on the horsepower definition.
Mechanical hp: The common US definition of horsepower. One mechanical hp equals 0.7457 kW.
Electric hp: A horsepower definition equal to 0.746 kW.
Metric hp (PS or CV): A horsepower definition equal to 0.735499 kW. PS and CV are labels commonly used for this definition.
Kilowatt (kW): A metric unit of power equal to 1,000 watts.
Rated output: The mechanical power a motor is rated to deliver at its shaft. It is not automatically the electrical power the motor draws.
Common mistakes and quick fixes
Mistake: Treating PS or CV as US mechanical horsepower.
Fix: Select "Metric hp (PS or CV)" before converting the rating.
Mistake: Entering a kW value while "Horsepower to kilowatts" is selected.
Fix: Switch "Conversion direction" to "Kilowatts to horsepower" before entering the value.
Mistake: Treating a converted motor nameplate rating as electrical input power.
Fix: Use it as rated shaft output, not electricity use. Real electrical input depends on load and efficiency; current or apparent-power estimates also require power factor.
Mistake: Typing a comma as a decimal mark, such as 7,5.
Fix: Use a decimal point for decimals, such as 7.5. Use commas only for thousands, such as 1,000.
Mistake: Rounding a small answer before using it in another calculation.
Fix: Open "Advanced options" and increase "Result decimal places" before copying the converted value.
Limitations & Key Assumptions / Boundary Conditions
- This calculator converts a stated power rating only. It does not calculate energy use, electricity cost, current, voltage, breaker size, or generator size.
- The selected horsepower definition must match the source. A PS or CV rating uses metric hp; a rating explicitly labeled electric hp uses electric hp.
- For a motor nameplate, the converted value is rated shaft output, not electricity use. Real electrical input depends on load and efficiency; current or apparent-power estimates also require power factor.
- The calculator accepts nonnegative rated magnitudes. It does not model signed power flow, startup demand, changing load, or peak power.
- Displayed decimal places round the answer for reading. Use more decimal places when copying a small value into another calculation.
Methodology
Conversion method
The calculator selects a kW-per-hp factor from the horsepower definition you choose: 0.7457 for mechanical hp, 0.746 for electric hp, and 0.735499 for metric hp. [1]
kW = hp x selected kW per hp factor
Use this equation when the entered source value is horsepower.
hp = kW / selected kW per hp factor
Use this reciprocal equation when the entered source value is kilowatts. The calculator keeps the selected factor visible so you can check which definition was used.
Worked example
For 100 mechanical hp, multiply 100 by 0.7457. The result is 74.57 kW. For the reverse direction, divide 7.46 kW by 0.746 to get 10 electric hp.
Scope of the calculation
The rating context does not change the arithmetic. Selecting "Motor nameplate" adds a reminder that horsepower converted to kW is rated shaft output, not a calculation of electrical input or energy consumption.