Power Converter
Convert watts, kilowatts, megawatts, horsepower (mechanical and metric) and BTU/h — electrical and mechanical power use the same units.
- InstantResults update as you type
- 27 categoriesFrom length to data storage
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How to use this tool
Steps for using the Unit Converter.
- Type a number into From — kilowatts are preselected. Commas and scientific notation such as 2.5e3 are accepted.
- Pick the units to convert between; the result in mechanical horsepower (or whichever unit you choose) updates as you type. Use the swap button to reverse the conversion.
- Set the decimal places, turn on Show formula to see the calculation, and copy or share the result.
- Below the converter, the table lists every power unit with its exact definition, and the links open dedicated pages for the most common pairs.
Example
150 kilowatts to mechanical horsepower
150 kW201.153313 hp
Formula: hp = kW × 1.34102209Common use cases
- Engine and motor ratings in kW and hp.
- Appliance and solar panel ratings in W and kW.
- Air-conditioner capacity in BTU/h.
Power unit table
| Unit | Symbol | System | Definition | In watts |
|---|---|---|---|---|
| Watt | W | SI | 1 J/s, the SI unit of power | 1 |
| Kilowatt | kW | Metric | 1,000 W | 1,000 |
| Megawatt | MW | Metric | 1,000,000 W | 1,000,000 |
| Mechanical horsepower | hp | Imperial | 550 ft·lbf/s ≈ 745.70 W | 745.6998715823 |
| Metric horsepower | PS | Metric | 75 kgf·m/s = 735.49875 W | 735.49875 |
| BTU per hour | BTU/h | US customary | ≈ 0.2931 W | 0.2930710702 |
Popular power conversions
Other unit converters
- Length convertermm · cm · m · km · in · ft · yd · mi · nmi
- Weight convertermg · g · kg · t · oz · lb · st
- Speed converterm/s · km/h · mph · ft/s · kn
- Volume convertermL · L · cm³ · m³ · gal (US) · qt (US) · cup (US) · fl oz (US) · gal (UK) · fl oz (UK)
- Temperature converter°C · °F · K
- Area convertermm² · cm² · m² · km² · in² · ft² · yd² · ac · ha
- Time converterms · s · min · h · d · wk
- Angle converter° · rad · gon · ′ · ″ · tr
About power units
Power is energy per unit of time; the watt is one joule per second. Electrical and mechanical power use the same units, so this converter covers both: a 2 kW heater and a 2 kW motor draw the same power.
Horsepower comes in two versions. Mechanical (imperial) horsepower is 550 foot-pounds-force per second, about 745.70 W, and is used in the US and UK. Metric horsepower (PS, CV, pk) is 75 kilogram-force meters per second, exactly 735.49875 W, and is used for cars in much of Europe and Asia. The two differ by about 1.4%.
Limitations
- Results are rounded for display only; the calculation keeps full precision (15 significant digits).
Frequently asked questions
How many watts is one horsepower?
Mechanical horsepower is 745.7 W; metric horsepower (PS) is 735.5 W.
Is electrical power different from mechanical power?
No — both are measured in watts. Electrical power is volts × amps (for DC), but the unit is the same.
What is the difference between kW and kWh?
kW measures power (a rate); kWh measures energy (power × time). Use the energy converter for kWh.
Are these power conversions exact?
Each unit is defined from its official definition (for example 1 inch = 2.54 cm exactly). Results are calculated in double precision and only rounded to the decimal places you choose when shown.