# How to convert watts to joules

How to convert electric power in watts (W) to energy in joules (J).

You can calculate joules from watts and seconds, but you can't convert watts to joules since watt and joule units represent different quantities.

### Watts to joules calculation formula

The energy *E* in joules (J) is equal to the power *P* in watts (W), times the
time period *t* in seconds (s):

*E*_{(J)} = *P*_{(W)}* *×* t*_{(s)}

So

joules = watts × seconds

or

J = W × s

#### Example

What is the energy consumption of an electrical circuit that has power consumption of 30 watts for time duration of 3 seconds?

*E*_{(J)} = 30W × 3s = 90J

How to convert joules to watts ►