Horsepower to Watts Converter

Power is the rate of doing work — how much energy is transferred each second — and its SI unit is the watt (W), one joule per second, named after James Watt. The scale climbs by thousands: kilowatts for kettles, motors and EV charging, megawatts for power stations, gigawatts for grids and terawatts for global demand. Horsepower comes from Watt himself, who coined it to compare steam engines with the horses they replaced. There are several versions: mechanical (imperial) horsepower is 550 foot-pounds per second, about 745.7 W and the figure behind most US car specs; metric horsepower — written PS in German or CV in French — is 75 kilogram-force metres per second, about 735.5 W, so a “100 PS” European car is slightly less powerful than a “100 hp” one; electrical horsepower is a round 746 W for motor ratings; and boiler horsepower is a much larger steam unit. Heating and cooling use their own units: the BTU per hour rates air conditioners and furnaces, and the ton of refrigeration — 12,000 BTU/h, about 3.517 kW — measures cooling capacity. The CGS system adds the tiny erg per second. One distinction worth keeping clear: power is not energy. A watt is a rate, while a watt-hour or joule is a total amount, so a kilowatt (kW) of power is different from a kilowatt-hour (kWh) of energy. This converter deals only in power. Every unit is stored as its exact number of watts, so any conversion is just the input turned into watts and then into the unit you want.