Power Converter
Convert between 18 different power units instantly.
Convert Watt to Kilowatt
Available Power Units (18)
Popular Power Conversions
About Power Conversion
Power measures the rate at which energy is transferred, converted, or used per unit time. The SI unit is the watt (W), defined as one joule per second. Power measurement is fundamental to electrical engineering, mechanical engineering, automotive performance, HVAC design, and energy management. From the watts rating on a light bulb to the horsepower of a car engine, power units quantify how quickly systems can perform work. Understanding power conversions is essential for comparing equipment specifications, calculating energy costs, and designing efficient systems.
Watts, Horsepower, and Beyond
The watt is the universal SI unit of power, but many specialized units persist. Mechanical horsepower (hp) equals approximately 745.7 watts and remains standard for rating engines and motors in the US. Metric horsepower (PS, from German Pferdestärke) equals approximately 735.5 watts and is used in European and Asian automotive specifications. Electrical horsepower equals exactly 746 watts. BTU per hour is used for heating and cooling capacity in the US — a typical home air conditioner might be rated at 24,000 BTU/h (about 7 kW or 2 tons of cooling). Understanding these relationships is crucial for equipment selection and energy planning.
Power in Electrical Systems
Electrical power is calculated as voltage times current (P = V × I). Household circuits in the US operate at 120V/15A or 120V/20A, providing 1,800-2,400 watts per circuit. A 240V circuit for an electric dryer provides about 5,760 watts. Electric vehicle chargers range from 1.4 kW (Level 1, standard outlet) to 350 kW (DC fast charging). Solar panel systems are rated in kilowatts peak (kWp), representing maximum output under ideal conditions. Power grids operate in megawatts (MW) and gigawatts (GW) — a typical nuclear reactor produces about 1 GW, enough for approximately 700,000 homes.
Mechanical and Automotive Power
Engine power determines vehicle performance. A typical family car produces 150-250 horsepower (112-186 kW). Sports cars range from 300-700 hp, while Formula 1 cars produce approximately 1,000 hp from hybrid power units. Electric motors deliver power differently than combustion engines — they provide maximum torque from zero RPM, which is why electric cars feel so responsive. When comparing vehicles across markets, converting between horsepower (US), PS (Europe/Asia), and kilowatts (increasingly used globally) is essential for accurate comparisons.
Power vs Energy: Understanding the Difference
Power and energy are related but distinct concepts that are often confused. Power is the rate of energy use (watts = joules per second), while energy is the total amount used over time (energy = power × time). A 100-watt bulb running for 10 hours uses 1,000 watt-hours (1 kWh) of energy. A 2,000-watt microwave running for 2 minutes uses only 67 watt-hours. This distinction matters for electricity billing (charged per kWh, not per watt), battery capacity (measured in watt-hours or amp-hours), and equipment sizing (rated in watts or horsepower for instantaneous capability).