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How these numbers are calculated

Every figure on this site is arithmetic on two inputs: a published electricity price and a stated usage assumption. Both are on the page, so you can check the work or substitute your own.

Where the prices come from

Average residential price per kilowatt-hour by state, from the U.S. Energy Information Administration's Electric Power Monthly, Table 5.6.A, which is compiled from Form EIA-861M. It is a work of the U.S. government and is in the public domain. The current edition on this site is June 2026, compared against June 2025. The build re-fetches it automatically; if the fetch fails, the previous month's figures stay in place rather than the site breaking.

These are averages of what customers actually paid: revenue divided by sales. That means fixed monthly charges, taxes and every rate plan in the state are already blended in. It also means no individual household pays exactly this rate.

The formula

For an appliance described by wattage:

kWh per year = watts ÷ 1000 × duty cycle × hours per day × days per year
cost = kWh × (cents per kWh ÷ 100)

Duty cycle is the share of "on" time the appliance actually draws power. A thermostatic device — a space heater, a fridge, a hot tub — reaches its setpoint and then cycles. Ignoring that is the single most common way running-cost estimates come out too high.

Appliances that are better described per load (dishwashers, dryers) use kWh per cycle × cycles per week × 52. Always-on thermostatic appliances (refrigerators, water heaters, EVs) use a whole-year kWh figure directly, because an hourly number for them would be meaningless.

Where the usage assumptions come from

Wattages are typical steady-draw figures for mainstream consumer models; hours and days are ordinary-use patterns. They are assumptions, not measurements, they are printed on every page that uses them, and they will not match your model exactly. The calculator exists so you can replace them with the number on your own appliance's label.

If you want a measurement rather than an estimate, a plug-in energy monitor costs about $25 and settles the question for any 120 V appliance in a week.

What this site does not do

It does not know your utility, your rate plan, your tier, your time-of-use window, your demand charges or your local taxes. Any of those can move your real cost well away from a statewide average. Treat these figures as a well-sourced estimate for comparison and planning, not as a bill.