How to convert watts to kWh
Energy in kWh = power in watts × hours of use ÷ 1,000. Then multiply by your price per kWh to get the cost. Your bill shows your price, or see the average electricity rate in your state.
Watts to kWh conversion table
| Watts | 1 hour | 8 hours | 24 hours |
|---|---|---|---|
| 10 W | 0.01 kWh · $0.00 | 0.08 kWh · $0.01 | 0.24 kWh · $0.04 |
| 60 W | 0.06 kWh · $0.01 | 0.48 kWh · $0.09 | 1.4 kWh · $0.26 |
| 100 W | 0.10 kWh · $0.02 | 0.80 kWh · $0.15 | 2.4 kWh · $0.44 |
| 500 W | 0.50 kWh · $0.09 | 4.0 kWh · $0.73 | 12.0 kWh · $2.20 |
| 1,000 W | 1.0 kWh · $0.18 | 8.0 kWh · $1.46 | 24.0 kWh · $4.39 |
| 1,500 W | 1.5 kWh · $0.27 | 12.0 kWh · $2.20 | 36.0 kWh · $6.59 |
Watts and kWh FAQ
How do I convert watts to kWh?
Multiply the watts by the hours of use, then divide by 1,000. A 100-watt device running for 10 hours uses 100 × 10 ÷ 1,000 = 1 kWh.
How many watts are in a kilowatt?
One kilowatt (kW) is 1,000 watts. A kilowatt-hour (kWh) is the energy used by 1,000 watts running for one hour.
What is the difference between watts and kWh?
Watts measure power: how fast a device uses energy at a given moment. Kilowatt-hours measure energy: power multiplied by time. Electric bills charge for kWh.
How much does 1 kWh cost?
U.S. homes paid an average of 18.31¢ per kWh in July 2026. Prices ranged widely by state; see our electricity rates by state page.
Electricity prices: U.S. Energy Information Administration retail sales data (July 2026). Last updated 2026-10-20.