Power Converter

Power is the rate of energy use or transfer — the SI unit is the watt (W = 1 J/s), named after James Watt of steam-engine fame. This converter handles all major power units: SI standard (watt, kilowatt = 1,000 W, megawatt, gigawatt), traditional mechanical (horsepower = 745.7 W in American/British usage, metric horsepower = PS = 735.5 W in continental European usage), American thermal (BTU per hour for HVAC capacity, foot-pound per second), and electrical engineering (volt-ampere for AC apparent power). Reference values: a typical LED bulb is 8–12 W, a microwave oven is 1,000–1,500 W, an electric car motor is 100–500 kW, and a nuclear reactor is 1,000–1,600 MW. The kilowatt dominates European appliance and motor ratings, while horsepower remains entrenched in American/British automotive marketing despite SI's preference for the watt. Use power conversion for appliance ratings, vehicle engines, electrical systems, HVAC sizing, and engineering specifications.

The watt is the base SI power unit, used worldwide for light bulbs, electrical appliances, and engine ratings.

The kilowatt is the standard power rating for European cars, household appliances, and small industrial motors.

The megawatt rates power plants, large industrial facilities, and grid-scale renewable installations worldwide.

Horsepower is the American and British unit for car engines, motorcycles, and traditional mechanical power ratings.

The Pferdestärke (PS) is the metric horsepower unit used in European car marketing and engine specifications.

BTU per hour is the standard rating for American heating, air-conditioning, and refrigeration system capacity.

The foot-pound per second is the American mechanical-power unit, used in engineering and machine-rating contexts.

The volt-ampere measures AC apparent power, used in transformer ratings, UPS sizing, and electrical engineering.

• ✓Power and energy are different. Power (watts) is rate of energy transfer; energy (joules, kWh) is the total amount.
• ✓1 kW = 1.34 hp (mechanical) = 1.36 hp (metric, PS in Germany).
• ✓Car engines: 80 kW typical city car; 200+ kW performance cars.
• ✓Home consumption averages 0.3–0.5 kW continuous (EU).

• ✗Treating kW (power) and kWh (energy) as interchangeable.
• ✗Mixing mechanical horsepower (745.7 W) and metric horsepower (735.5 W).
• ✗Using BTU (energy) instead of BTU/h (power) on HVAC specs.
• ✗Confusing VA (apparent power) with W (real power) in electronics.