Power Conversions
Convert power units — watts, horsepower, kilowatts, BTU/h. Free calculators for engines, appliances, and electrical load.
9 units · 8 conversions
Power is the rate of energy transfer — how fast work is done. Electric motors and heaters use watts or kilowatts; cars and lawn equipment quote horsepower; HVAC sometimes uses BTU per hour.
Mechanical horsepower (US) equals 745.7 watts. Metric horsepower (PS) is slightly different (~735.5 W). Our converters specify which horsepower definition applies.
Popular power conversions
Real-world example
A portable generator is rated 3,500 W and you want to compare it to a 5.5 hp pressure washer. Converting 5.5 hp ≈ 4,100 W shows the generator can run the washer if starting surge allows.
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Power units explained
- Watts (W) · base unit
- Also: watts
- Kilowatts (kW)
- Also: kilowatts
- Megawatts (MW)
- Also: megawatts
- Horsepower (Mechanical) (hp)
- Also: horsepower, hp, mechanical horsepower
- Horsepower (Metric) (PS)
- Also: metric horsepower, ps, pferdestärke
- Horsepower (Electric) (hp)
- Also: electric horsepower
- BTU per Hour (BTU/h)
- Also: btu per hour, btu/hr
- Calories per Second (cal/s)
- Also: calories per second
- Foot-pounds per Second (ft·lbf/s)
- Also: foot pounds per second
Frequently asked questions
- How many watts are in one horsepower?
- One US mechanical horsepower equals 745.699872 watts (often rounded to 746 W).
- Is power the same as energy?
- No. Power is rate (watts); energy is total amount (watt-hours or joules). Energy = power × time.