kWh to Watts Calculator

How it works

Average watts = kWh × 1,000 ÷ hours. Average kilowatts = kWh ÷ hours. For example, 1 kWh used over 24 hours is 41.7 W, or 0.0417 kW, on average.

Worked example: 10 kWh used over 5 hours

Multiply 10 kWh by 1,000 to get 10,000 watt-hours, then divide by 5 hours. The result is an average power draw of 2,000 W.

If the same 10 kWh were spread over 24 hours, the average would be about 417 W. The energy is unchanged; only the time period changes the average power.

Why kWh cannot become watts without a time period

Kilowatt-hours measure energy used, while watts measure the rate at which energy is being used. A monthly bill can show total kWh, but it cannot reveal a device’s watts unless you know how long that device actually ran.

For cycling equipment such as refrigerators, air conditioners and heat pumps, this calculation smooths starts, stops and power spikes into one average. Use a plug-in meter or circuit monitor when you need live or peak watts.

Convert daily or monthly kWh to average watts

For a daily meter total, enter the energy used and 24 hours. A home using 10 kWh per day averages about 417 W across the full day.

For a 30-day bill, use 720 hours (30 × 24). A bill showing 300 kWh over 30 days represents the same 417 W round-the-clock average. This does not mean the home draws exactly 417 W every moment; real demand rises and falls as equipment switches on and off.

Sources used for assumptions: U.S. Energy Information Administration — Measuring electricity.

Frequently asked questions