Everyday Tools

What Is a Kilowatt-Hour (kWh)?

A kilowatt-hour (kWh) is a unit of energy equal to using 1,000 watts of power for one hour. It is the unit electricity suppliers use to bill households. Energy in kWh = power in watts × hours of use ÷ 1,000.

Example

A 1,500-watt heater running for 2 hours uses 3 kWh. At 0.20 per kWh, that costs 0.60.

Watts vs. Watt-Hours

Watts measure the rate of energy use at a moment; watt-hours and kilowatt-hours measure total energy used over time.

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Last updated: September 27, 2026. This definition is for general educational purposes only. It is not financial, investment, tax, legal, or medical advice, and it does not recommend any product or course of action. For decisions about your own situation, consult a qualified professional.