How much does it cost to run an appliance?
Pick an appliance, tell us how long it runs, and see the cost at your state's average electricity price.
The short answer
Multiply the appliance's wattage by the hours you use it and divide by 1,000 to get kWh. Then multiply by your rate. A 1,500 W space heater running 4 hours a day uses 180 kWh a month, which costs $32.96 at the U.S. average of 18.31¢ per kWh.
Where you live matters. The same heater costs $86.40 a month in Hawaii (48¢/kWh) and $22.90 in Louisiana (12.72¢/kWh).
The space heater example, step by step
- Watts × hours a day1,500 W × 4 h = 6,000 Wh
- Divide by 1,000 to get kWh6 kWh a day
- Times 30 days180 kWh a month
- Times the rate (18.31¢ per kWh)$32.96 a month
Think of a kilowatt-hour as a "gallon" of electricity. A 1,000 W appliance burns through one kWh in an hour; a 100 W one takes ten hours to use the same amount.
What common appliances use in a month
Using typical wattage and hours. Your model may use more or less, so check its label.
How we calculate
Cost = watts × hours a day × days ÷ 1,000 × rate ($/kWh)
Rates: U.S. Energy Information Administration, Electric Power Monthly, Table 5.6.A, average residential price for July 2026. It is total residential revenue divided by kWh sold, so it already folds in fees and taxes on the bill. The EIA publishes these figures about three months after the fact.
Frequently asked questions
Where do I find my appliance's wattage?
On the label or nameplate, usually on the back or bottom, or in the manual. If it only lists amps, multiply amps by volts (120 V for most outlets, 240 V for dryers and ovens).
How do I calculate a refrigerator, since it cycles on and off?
Use the yearly kWh on the yellow EnergyGuide label. Divide it by 8.76 to get the average wattage over 24 hours. A fridge rated at 500 kWh a year averages about 57 W.
Why is my bill higher than this?
Your bill covers every device in the house plus a fixed monthly customer charge. Some utilities also use tiered or time-of-use rates, so your price per kWh can differ from the state average.
Where do I find my exact rate?
Take the total on your bill and divide it by the kWh used that month. That gives your all-in price per kWh, which you can type into the rate box.