Electricity Cost Calculator

How to use this calculator

1. Choose a device from the list, or pick Enter watts myself and type the wattage from the label.
2. Enter how many you’re running (useful for light bulbs), the hours per day and the days per week you use it.
3. Pick your state to use its average residential electricity rate, or choose Enter my own rate and type the rate from your bill.

The result shows the cost per month with the cost per year beside it, then the cost for each day of use and the energy in kilowatt-hours per day, month and year. The table below compares common household appliances at the same rate, so you can see where your money actually goes.

The formula

Electricity is billed in kilowatt-hours (kWh): one kilowatt (1,000 watts) running for one hour.

For a year, the calculator multiplies the daily kWh by the days per week and by 52.14 weeks (365 ÷ 7). A month is a twelfth of that, so it’s an average month, not a particular 30 or 31 days.

Worked example

The default is a 1,500 watt device, the most a standard plug-in space heater draws, running 8 hours a day, every day, at the U.S. average rate of 18.19¢ per kWh:

1. Power: 1,500 W = 1.5 kW.
2. Energy per day: 1.5 kW × 8 h = 12 kWh.
3. Per year: 12 × 7 × 52.14 = 4,380 kWh; per month 365 kWh.
4. Cost: $2.18 a day, $66.39 a month and $797 a year.

Use it only on weekdays (5 days a week) and the cost falls to $47.42 a month. An electric dryer (5,000 W) running one hour, three times a week, costs about $11.86 a month.

Electricity prices by state

Prices vary threefold across the country, so the same appliance can cost very different amounts. Here is the 1,500 W heater from the example, 8 hours a day, and a Level 2 EV charger (7.2 kW) running 1.5 hours a day:

The rates are the EIA’s average residential price for January through August 2026, which smooths out the summer peak better than a single month. The cheapest states were North Dakota, Nebraska and Idaho; the most expensive were Hawaii, California, Maine and Massachusetts. Every state is in the calculator’s list.

Typical appliance wattages

The device list uses these draws. Most come from the Department of Energy’s table of typical nameplate wattages, which gives a range for each appliance; a few modern devices are worked out from their ratings:

• Kitchen: coffee maker 1,000 W (DOE range 900–1,200), microwave 1,100 W (750–1,100), toaster oven 1,225 W, dishwasher 1,800 W (1,200–2,400; the heated dry cycle is a big part of it).
• Laundry: clothes washer 500 W (350–500, not counting hot water), electric dryer 5,000 W (1,800–5,000).
• Comfort: ceiling fan 75 W (65–175), dehumidifier 785 W, space heater 1,500 W (750–1,500). A window air conditioner draws its BTU rating divided by its efficiency (EER), so a 10,000 BTU unit with an EER of 11 draws about 909 W; a 3-ton (36,000 BTU) central system at EER 12 draws about 3,000 W while the compressor runs.
• Everything else: flat-screen TV 120 W, laptop 50 W, 60 W-equivalent LED bulb 9 W, a 40-gallon electric water heater 4,500 W (4,500–5,500), and a Level 2 EV charger 7,200 W (240 volts × 30 amps).
• Refrigerator: a fridge cycles all day, so the list uses its average draw. The median full-size refrigerator-freezer in ENERGY STAR’s certified-product data is rated at 478 kWh a year, about 55 W around the clock. Top-freezer models came in at a median of 363 kWh and side-by-sides at 642 kWh.

Tips to cut the cost

• Heating and cooling come first. The EIA’s 2020 survey found air conditioning was 19% of home electricity use, space heating 12% and water heating 12%. A degree or two on the thermostat matters more than unplugging a phone charger. Sizing a new unit? The BTU calculator uses the ENERGY STAR chart.
• Watch the big resistive loads. Anything that makes heat with electricity, like heaters, dryers, ovens and water heaters, draws 1,500 to 5,000 watts. Shorter use, lower settings or a heat-pump version saves the most.
• Thermostats change the math. Heaters, ACs and fridges cycle on and off, so 8 hours “on” may be 4 hours of actual running. A plug-in meter shows real use.
• Check your actual rate. Your bill may have tiers, time-of-use pricing or fixed charges. Divide the total by the kWh used for your all-in rate.
• Thinking about solar or an EV? The solar calculator estimates what panels could offset, and the gas cost calculator compares driving costs with an EV at your electricity price.

Assumptions and limitations

• Device wattages are typical values. The label shows a maximum; many devices draw less most of the time.
• State rates are averages across all utilities and customers in the state, including fixed charges spread over usage. Your utility’s rate can be higher or lower.
• The calculator doesn’t model time-of-use pricing, tiered rates or demand charges.
• Costs are for electricity only. Hot water used by a washer or dishwasher is heated by your water heater and isn’t included here.

Sources

• U.S. Energy Information Administration: Electric Power Monthly, Table 5.6.B, average price of electricity by state, year-to-date through August 2026 (released October 23, 2026)
• U.S. Energy Information Administration: Electricity use in homes
• U.S. Department of Energy typical appliance wattages, as reproduced by the Utah Division of Water Rights (PDF)
• ENERGY STAR: Certified residential refrigerators dataset (annual energy use by model)

Updated November 2026. Results are estimates for educational purposes and depend on the inputs you provide.