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What do watt and kWh mean?

The difference is quite simple, but many people muddle them up.

Watts (W)

A watt (W) is a unit of measurement of power. Watts therefore refer to the power of your device.


  • an incandescent lamp has a power of 60 W
  • your microwave oven has a maximum power of 900 W

The watt, as its many variations – kilowatt, megawatt, etc. – measures the electrical power of a device, whether it is a motor, a machine or the heating capacity of a boiler or wood stove. Today, this information appears on the technical descriptions for all electrical appliances.

The more powerful a device is, the higher the number of watts.

Variations on watts:

  • 1 kilowatt (kW) = 1,000 watts (W)
  • 1 megawatt (MW) = 1,000 kilowatts (kW)
  • 1 gigawatt (GW) = 1,000 megawatts (MW)

Here is a list of appliances with their power (in watts) and their consumption (in kWh).

Kilowatt hours (kWh)

A kilowatt hour (kWh) is a unit of measurement of energy. A kilowatt hour therefore refers to the consumption of your device.

1 kilowatt hour (kWh) is the energy consumed by a 1,000-watt or 1-kilowatt electrical appliance operating for 1 hour.


  • a 60 W lamp that burns for one hour will have consumed 60 Wh or 0.06 kWh
  • a 900 W microwave oven that runs for 5 minutes will have consumed 75Wh or 0.075 kWh

Variations on kilowatt hours:

  • 1 kilowatt hour (kWh) = 1,000 watt hours (Wh)
  • 1 megawatt hour (MWh) = 1,000 kilowatt hours (kWh)
  • 1 gigawatt hour (GWh) = 1,000 megawatt hours (MWh)

Here you will find how to calculate the consumption of your electrical device yourself

Did you know...
The watt and the kilowatt hour owe their name to James Watt, a Scottish engineer born in 1736 who invented the steam engine.

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