Power Converter
This power converter accepts a value in watts and converts it to kilowatts, horsepower, BTU per hour, and megawatts. It bridges electrical, mechanical, and thermal power measurement for appliance ratings, engine specs, and power plant output.
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Formula
kW = W ÷ 1000 | hp = W ÷ 745.7
The watt is the SI unit of power, equal to one joule per second. One kilowatt is 1,000 watts. One mechanical horsepower is exactly 550 foot-pounds per second, which equals 745.69987 watts. One BTU per hour equals 0.293071 watts, making the conversion factor 3.41214 watts per BTU/hr. One megawatt is 1,000,000 watts.
How to use the Power Converter
- 1
Enter your power (watts)
Enter power in watts to convert to kilowatts, horsepower, and other units.
- 2
Read your results instantly
Results update in real time as you type.
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Power Units in Electrical and Mechanical Contexts
Power is the rate at which energy is transferred or converted. In electrical engineering, power is measured in watts (W), kilowatts (kW), and megawatts (MW). Household appliances are rated in watts; power plants in megawatts. In automotive and mechanical engineering, engine output is rated in horsepower (hp) — with mechanical horsepower used in the US and metric horsepower (PS) common in Europe, Japan, and Korea. HVAC equipment in the US is rated in BTU per hour for thermal power. Understanding all three unit families is essential for anyone working across these domains.
Power Consumption Reference Points
Everyday power figures span a wide range. A smartphone charger uses about 5–20 watts. A LED light bulb uses 8–12 watts. A desktop computer uses 100–400 watts. A microwave oven uses 800–1,200 watts (0.8–1.2 kW). An electric car motor produces 100–500 kW (134–670 hp). A commercial aircraft engine produces about 100,000 hp (about 75 MW). A large nuclear power plant produces about 1,000 MW (1 GW). These reference points help contextualize power ratings across familiar technologies.
Tips & Insights
Watts vs. Watt-Hours
Watts measure power (rate of energy use), while watt-hours (Wh) measure energy (total amount used). A 100-watt bulb running for 10 hours uses 1,000 Wh = 1 kWh. Electricity bills charge you for kWh, not watts.
Mechanical vs. Metric Horsepower
US car specs use mechanical horsepower (1 hp = 745.7 W). European and Japanese vehicles may use metric horsepower or PS (Pferdestärke), where 1 PS = 735.5 W — about 1.4% less than US hp. At 200+ hp levels, this difference is noticeable.
BTU/hr for Air Conditioners
Window air conditioners are rated in BTU/hr. A 10,000 BTU/hr unit draws about 2,930 watts (2.93 kW). Divide BTU/hr by 3.412 to convert to watts, or multiply watts by 3.412 to get BTU/hr.
Worked Examples
Convert 1 Horsepower to Watts
745.7 W (1 mechanical horsepower) equals 0.7457 kW, 1 hp, 2,544.4 BTU/hr, and 0.0007457 MW.
Convert 100 kW Electric Motor
100,000 W (100 kW) equals 100 kW, 134.1 hp, 341,214 BTU/hr, and 0.1 MW.
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Frequently Asked Questions
How many watts are in a horsepower?
One mechanical horsepower (as used in US automotive specs) equals 745.7 watts. One metric horsepower (PS) equals 735.5 watts. The difference is about 1.4%.
What is the difference between watts and kilowatts?
A kilowatt (kW) is simply 1,000 watts. The prefix 'kilo' always means one thousand in the SI system. Household appliances use watts; larger equipment and power consumption are stated in kilowatts or megawatts.
How do I convert BTU/hr to watts?
Divide BTU per hour by 3.41214 to get watts. Alternatively, multiply BTU/hr by 0.29307. For example, 10,000 BTU/hr ÷ 3.412 = 2,930 watts.
What is the difference between power and energy?
Power is the rate of energy transfer (watts), while energy is the total amount transferred (joules or watt-hours). A 100-watt light bulb (power) running for 1 hour uses 100 watt-hours (energy). Electricity bills charge for energy (kWh), not power (kW).
How much power does a nuclear plant generate?
A typical large nuclear power plant generates about 1,000 megawatts (1 GW) of electrical power. This is enough to power about 750,000 to 1 million average US homes simultaneously.
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