# Energy calculator

## This tool calculates the amount of energy produced by electrical power.

Inputs
Power
Time
Output
Energy in joules
EEnergy in watt hours

### Equations

Electric power is the rate of doing work, measured in watts, and represented by the letter P. The term wattage is used to mean "electric power in watts." The electric power in watts produced by an electric current I consisting of a charge of Q coulombs every t seconds passing through an electric potential (voltage) difference of V is:

$$P = work done per unit of time = VQ/t = (V)(I)$$

or

$$Power = Voltage x Current or Volts x Amperes$$

where: Q is electric charge in coulombs, t is a time in seconds, I is an electric current in amperes and V is electric potential or voltage in volts

### Applications

Electric Power is the rate at which electricity does work or provides energy. The SI unit of power is the watt, one joule per second.

Electric power is usually produced by electric generators, but can also be supplied by electric batteries. Electric power is usually sold by electric companies as the kilowatt-hour (3.6 MJ) which is the product of power in kilowatts multiplied by running time in hours. Electric utilities measure power using an electricity meter, which keeps a running total of the electric energy delivered to a customer.