What unit is used to measure energy?

The unit used to measure energy is the joule. The joule is a derived SI (International System of Units) unit that quantifies the amount of energy transferred when one newton of force is applied over a distance of one meter. It is also equivalent to one watt per second, which links energy to power and time.

Other options include watts, which measure power—defined as the rate at which energy is transferred or converted; newtons, which measure force; and pascals, which measure pressure. Each of these units serves a distinct purpose in scientific measurements, but only the joule is specifically designed to measure energy.