Free Power Converter
Convert between watts, kilowatts, horsepower, BTU/hr, and foot-pounds/second. Instant power unit conversion for engineering and automotive.
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1 Horsepower (mechanical) =
Formula
Converted Value = Input Value × (Source Unit in watts) ÷ (Target Unit in watts)How to Convert Power Units
Power measures the rate of energy transfer or work done per unit time. This converter normalizes all values to watts (the SI unit) and converts between the most common power units used in engineering, automotive, and HVAC applications.
Power Units Explained
- Watts (W) — the SI unit of power. 1 watt = 1 joule per second.
- Kilowatts (kW) — 1,000 watts. Used for electrical appliances and EV motors.
- Megawatts (MW) — 1,000,000 watts. Used for power plants and large installations.
- Horsepower (mechanical) — 745.7 watts. Standard in the US for engines and motors.
- Horsepower (metric/PS) — 735.5 watts. Used in Europe and Japan for vehicle specs.
- BTU/hour — used for HVAC systems and heating. 1 BTU/hr ≈ 0.293 watts.
- Foot-pounds/second — used in mechanical engineering. 1 ft·lbf/s ≈ 1.356 watts.
Common Power References
- LED light bulb: 10 watts
- Microwave oven: 1,000-1,200 watts
- Average car engine: 150-300 HP (112-224 kW)
- Tesla Model 3 motor: 283 HP (211 kW)
- Hoover Dam: 2,080 MW
Frequently Asked Questions
How do I convert horsepower to watts?
Multiply mechanical horsepower by 745.7 to get watts. For example, 200 HP × 745.7 = 149,140 watts ≈ 149.1 kW. For metric horsepower, multiply by 735.5.
What is the difference between mechanical and metric horsepower?
Mechanical (imperial) horsepower = 745.7 watts. Metric horsepower (PS/CV) = 735.5 watts. European car specs typically use metric HP (PS), while US specs use mechanical HP.
How many watts is a typical household?
A typical US household uses an average of 1,200 watts continuously (about 30 kWh per day). Peak usage during summer AC can reach 5,000-10,000 watts.
What is a watt?
A watt is one joule per second — the rate of energy transfer. It's named after James Watt. A 100W light bulb uses 100 joules of energy every second.
How do BTU/hr relate to HVAC systems?
HVAC systems are rated in BTU/hr. A typical window AC unit is 5,000-12,000 BTU/hr. To convert to watts, multiply BTU/hr by 0.293. A 12,000 BTU/hr AC ≈ 3,517 watts ≈ 1 ton of cooling.