# How to convert watts to kilojoules

How to convert electric power in watts (W) to energy in kilojoules (kJ).

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

### Watts to kJ calculation formula

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

*E*_{(kJ)} = *P*_{(W)}* *×* t*_{(s)}
/ 1000

So

kilojoules = watts × seconds / 1000

or

kJ = W × s / 1000

#### Example

What is the energy consumption of an electrical circuit that has power consumption of 300 watts for time duration of 3 seconds?

*E*_{(kJ)} = 300W × 3s / 1000 = 0.9kJ