What’s a Watt?


We are confronted every day by the notions of energy and power: cars and motors are sold by horsepower, light bulbs by watts, natural gas by therms, electricity by kilowatt-hours, and air conditioners by tons or BTUs per hour. Is energy the same as power? If not, what’s the difference, and how do all of these units relate to each other?

Use this interactive calculator to simply find out how energy is measured, consumed, and used.