Electricity cost calculator

How the calculation works

Electricity is billed by the kilowatt-hour, the energy used by something drawing 1,000 watts for an hour. So the cost of running an appliance is its power in kilowatts, times the hours it runs, times your price per kWh:

cost = watts ÷ 1,000 × hours × rate

A 1,500-watt heater uses 1.5 kWh in an hour. At 18.3¢ per kWh, that hour costs $0.27. Eight hours a day for a year comes to 4,380 kWh and about $802.

What common appliances cost per hour

These are typical wattages from Virginia Cooperative Extension, priced at the U.S. average rate. Where the source gives a range, the cost uses the middle of it. Your own appliance may sit anywhere in the range, and the label on it is the better number.

When the label overstates what you pay

The wattage on a label is the most the appliance draws, and many appliances do not draw it all the time. A refrigerator's compressor switches on and off through the day. A space heater on a thermostat stops heating once the room is warm. A dryer's heating element cycles as the drum gets hot. For these, hours of use overstates the real cost, sometimes by half or more.

The reverse happens with things that never really switch off. A TV, a game console or a set-top box on standby draws a few watts around the clock, and 8,760 hours a year adds up. If you want a real figure for a specific appliance, a plug-in power meter measures what it actually uses over a day or a week, and the kWh it reports can go straight into the calculation above.

Using your own rate

The state figure is the average across every residential customer, including fixed monthly charges spread over usage. Your utility's rate can be higher or lower, and some plans charge more at peak times or above a monthly threshold. The most accurate number is your own: take the total on a recent bill and divide it by the kWh used. To see how your state compares with the rest of the country, the electricity rates by state table has every state's latest price, and the average electric bill by state shows what those rates add up to over a month. If the appliance you are pricing is a heater, the space heater cost calculator also accounts for thermostat cycling.