# Power Conversions

## Select a unit of power

Power is the rate at which energy is transformed or work is done.

The standard derived unit of power in the International System of Units (SI) is the watt (W). Other units of power commonly in use throughout the world include kilowatts, megawatts, gigawatts, British thermal units per hour, Celsius heat units per hour, calories per hour, calories per day, kilocalories per hour, foot-pound-force per second, inch-pound-force per second, liter-atmosphere per second and horsepower.

## Common power conversions

• 1 watt = 1,000 milliwatts = 1,000,000 microwatts
• 1 kilowatt = 1,000 watts = 1,000,000 milliwatts
• 1 gigawatt = 1,000 kilowatts = 1,000,000 watts
• 1 horsepower (metric) = 735.49875 watts = 0.73549875 kilowatts
• 1 British thermal unit (IT) per hour = 0.29307107 watts
• 1 British thermal unit (59 °F) per hour = 0.293001111 watts
• 1 calorie (IT) per hour = 0.001163 watts
• 1 erg per second = 10-7 watts
• 1 foot-pound-force per second = 1.355817948 watts
• 1 ton of refrigeration (IT) = 3,516.853 watts

## Units of power measurement

Conversions from and to various units of power.