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Kilowatt-hour (kWh)

Quantity: Energy · Category: Non-SI

The kilowatt-hour is a unit of energy equal to one kilowatt of power sustained for one hour. It is the standard billing unit for electrical energy worldwide.

Relation to SI

1 kWh = 1000 W × 3600 s = 3.6×10⁶ J

Examples

  • A 100 W bulb burning for 10 hours uses 1 kWh.
  • A typical US home uses roughly 900 kWh per month.
  • Charging an electric car may add 30–60 kWh to the bill.