Free online power converter. Select any unit pair below or use the interactive converter.
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Power measures the rate at which energy is transferred or work is done — essentially, how fast energy flows. It is one of the most important quantities in electrical engineering, mechanical engineering, and energy management. The challenge is that different industries use different units: electricians use watts and kilowatts, mechanics use horsepower, HVAC engineers use BTU/hour, and European automotive specs use metric horsepower (PS). Accurate power conversion is essential for comparing engines, understanding electricity bills, and designing systems.
Quick reference for the most commonly used power conversions:
| From | To | Multiply By |
|---|---|---|
| Horsepower (hp) | Kilowatt (kW) | 0.7457 |
| Kilowatt (kW) | Horsepower (hp) | 1.34102 |
| Metric HP (PS) | Kilowatt (kW) | 0.735499 |
| Kilowatt (kW) | Metric HP (PS) | 1.35962 |
| Watt (W) | BTU/hour | 3.41214 |
| BTU/hour | Watt (W) | 0.293071 |
| Megawatt (MW) | Horsepower (hp) | 1,341.02 |
| Horsepower (hp) | Metric HP (PS) | 1.01387 |
| Unit | Symbol | Value | Used In |
|---|---|---|---|
| Watt | W | SI base unit | Electronics, appliances |
| Kilowatt | kW | 1,000 W | Home power, engines |
| Megawatt | MW | 1,000,000 W | Power plants, large industry |
| Mechanical Horsepower | hp | 745.7 W | US/UK engines, pumps |
| Metric Horsepower | PS | 735.5 W | European automotive |
| BTU/hour | BTU/h | 0.2931 W | HVAC, air conditioning |
1 mechanical horsepower (hp) = 745.7 watts. The metric horsepower (PS, used in Europe) = 735.499 watts — slightly less than the mechanical hp used in the US and UK.
hp (mechanical horsepower) = 745.7 W — used in the US, UK, and India. PS (Pferdestärke, metric horsepower) = 735.5 W — used in Germany and most of Europe for car specs. 1 hp = 1.01387 PS — they are very close but not identical.
Multiply by 1.34102. For example, 100 kW engine = 100 × 1.341 = 134.1 hp. To go from hp to kW, multiply by 0.7457.
BTU/hour (British Thermal Unit per hour) is used to measure the heating or cooling capacity of HVAC systems, air conditioners, and furnaces — especially in the United States. 1 BTU/hour = 0.293 watts.
1 megawatt (MW) = 1,000 kilowatts (kW) = 1,000,000 watts. A large wind turbine typically generates 2–3 MW — enough to power 500–1,000 homes.
"1 ton" AC = 12,000 BTU/hour = 3,517 watts ≈ 3.5 kW. It originally referred to the amount of heat needed to melt one ton of ice in 24 hours — now a standard rating for cooling capacity.