# How to convert watts to watt-hours

How to convert electric power in watts (W) to energy in watt-hour (Wh).

You can calculate watt-hour from watts and hours, but you can't convert watts to watt-hour, since watts and watt-hour units represent different quantities.

### Watts to watt-hour calculation formula

The energy *E* in watt-hour (Wh) is equal to the power *P* in watts
(W), times
the time period *t* in hours (h):

*E*_{(Wh)} = *P*_{(W)}* *×* t*_{(h)}

So

watt-hour = watts × hours

or

Wh = W × h

#### Example

What is the energy consumption in watt-hour when the power consumption is 5 watts for time duration of 3 hours?

*E* = 5W × 3h = 15 Wh