kWh calculator
How much electricity a device uses in a month, and what it costs with plans available in your area.
Fills in typical power and hours. Change them below to match yours.
Used in a month.
A month at 13.2¢/kWh, the typical plan price in Texas.
Device wattages are typical values; the label on your device shows its real power. Air conditioners and heaters cycle on and off, so actual hours of full power are often lower than hours of use.
Estimating electric heating? Use the space heater cost calculator to enter your own rate and account for thermostat cycling.
Questions people ask
How do I calculate kWh?
Multiply the device’s power in watts by the hours it runs, then divide by 1,000. A 1,500-watt heater running 4 hours a day for 30 days uses 1,500 × 4 × 30 ÷ 1,000 = 180 kWh.
What uses the most electricity in a Texas home?
Air conditioning, by far, in summer. Electric water heaters, dryers and pool pumps come next.