What this converter does
This converter turns a power rating in kilowatts into the energy it uses in kilowatt-hours over a chosen time — or the reverse. Enter the kW and the number of hours and read the kWh. It is how you go from a device’s rating to what it adds to your bill.
Energy equals power multiplied by time. A 2 kW appliance running 3 hours uses 6 kWh. To work back from a metered figure, see the kWh to kW converter.
The units it covers
Power and energy are different quantities — one is a rate, the other is a total. Time links them.
View all units & their values
| Unit | Symbol | Value | Mainly used |
|---|---|---|---|
| Power | kW | P | The rate energy is used |
| Energy | kWh | E | What the meter bills; battery capacity |
| Time | h | t | How long the power runs |
| Watt-hour | Wh | — | 1 kWh = 1,000 Wh |
The formula
Energy is the power multiplied by the time it runs:
kWh = kW × hours (and kW = kWh ÷ hours)Where:
- kW = the power rating, in kilowatts
- hours = the time the device runs
- kWh = the resulting energy used
Worked example
A 2 kW appliance runs for 3 hours. Find the energy it uses.
kWh = kW × hours2 × 3 = 6 kWhThe appliance uses 6 kWh — the figure your meter and bill record.
The units in this example
The rate at which a device uses energy. Held for a length of time it accumulates into kilowatt-hours, the unit you are billed on.
- kWh = kW × hours
- 2 kW for 3 h = 6 kWh
- 1 kW = 1,000 watts
- 1 kW for 24 h = 24 kWh
A kilowatt-hour is one kilowatt sustained for an hour. It is the billed unit of electricity and the way battery and solar capacity is stated.
- 1 kWh = 1 kW for 1 hour
- 1 kWh = 1,000 Wh
- kW = kWh ÷ hours
- 6 kWh ÷ 3 h = 2 kW
FAQ
Sources
US EIA — energy units & calculators · US DOE — estimating energy use