How to use kWh to Watts
Enter the energy used in kilowatt hours and the number of hours it was used over. The result is the average power in watts.
Worked example
A fridge that uses 12 kWh over 24 hours has an average draw of 12 × 1,000 ÷ 24 = 500 watts. A heater that used 3 kWh in 2 hours averaged 1,500 watts. Because many appliances cycle on and off, the average is often well below the power printed on the label.
kWh and kW are different things
Watts and kilowatts measure power, how fast energy is used right now. Kilowatt hours measure energy, the total used over time. Your electricity bill charges for kWh. To estimate cost, multiply the kWh by your price per kWh: 12 kWh at $0.20 is $2.40.
The formula
watts = kWh × 1,000 ÷ hours
Examples
- 2 kWh over 4 hours
500 W average power 2,000 Wh over 4 hours.
- 12 kWh over 24 hours
500 W average power 12,000 Wh over 24 hours.
- 0.9 kWh over 1.5 hours
600 W average power 900 Wh over 1.5 hours.
Limitations and assumptions
Energy and power are different quantities, so a time period is required.
Frequently asked questions
How do I convert kWh to watts?
Watts = kWh × 1,000 ÷ hours.
Are kWh and kW the same?
No. A kilowatt is power; a kilowatt hour is that power held for an hour.
What does the result mean?
The average power draw over the time period.
How much will it cost?
Multiply kWh by your electricity rate.