Electricity Cost Calculator

Electricity is sold by the kilowatt-hour, so every electricity cost question reduces to two numbers: how many kilowatt-hours were consumed, and what one kilowatt-hour costs. This calculator keeps both visible. In watts mode it converts power and runtime into energy; in kWh mode it takes a figure you already measured from a meter, a statement or a plug-in energy monitor. Either way the arithmetic stays the same, and nothing is hidden behind a lead form or an account.

The kWh cost you enter should be the marginal energy price from your tariff, not the total bill divided by usage. Dividing a statement total by kilowatt-hours folds the fixed customer charge and taxes into an all-in average that overstates the cost of running one more appliance. Selecting a state loads the U.S. Energy Information Administration average residential price for the 2024 annual vintage, which is a sound national benchmark and a poor substitute for your own rate schedule.

Results are normalized so two unequal periods can be compared. Cost per day divides the period cost by the days entered. The monthly figure multiplies that daily cost by 30.437, the average length of a calendar month across a four-year cycle, and the yearly figure multiplies it by 365. Those conversions are deliberate: a 28-day February statement and a 31-day August statement are not comparable until both are expressed as a rate.

Assumptions and edge cases

The model assumes a single flat energy price and a constant average power over the runtime you enter. It does not know about tiered blocks, seasonal schedules, time-of-use windows, demand charges, fuel adjustments, minimum bills or net-metering credits. Quantity multiplies identical units, so three identical 60 W fixtures on the same schedule are entered as quantity three rather than 180 W. Entering zero days returns a zero period cost and suppresses the derived daily, monthly and yearly values instead of dividing by zero, and negative inputs are rejected rather than silently treated as savings.

Worked examples

A central air conditioner drawing an average 3,500 W while the compressor runs, operating 6 hours a day for 30 days, uses 3,500 × 6 × 30 ÷ 1,000 = 630 kWh. At the 16.48¢ national benchmark the electricity cost is $103.82 for the month, $3.46 a day and roughly $1,263 if that pace continued all year. It will not: cooling is seasonal, which is why the yearly line is a pace, not a forecast.

For a second case, take a whole-home reading instead of one appliance. A meter that advances 892 kWh over a 31-day billing period, priced at a California-style 31.87¢ rate, gives 892 × 0.3187 = $284.28 in energy charges, or $9.17 a day. Switching the same 892 kWh to a Washington-style 11.9¢ rate gives $106.15. The usage did not change; only the price of a kilowatt-hour did, and that single factor explains most of the difference between household electricity expenses across the country.

How to read the result

Use thresholds rather than exact dollars. A load under about $5 a month is rarely worth chasing; between $5 and $20 a month a schedule change or a setpoint adjustment usually pays for itself immediately; above $20 a month the appliance is a genuine candidate for replacement, and above $50 a month it is worth measuring the actual power draw before spending anything. If your modeled figure lands within about 10 percent of the energy line on a statement, the assumptions are good enough to act on. A gap larger than 25 percent almost always means the runtime is wrong, the load cycles rather than running continuously, or the statement includes charges this energy-only calculation deliberately excludes.

People search for this in several ways — electricity cost, electricity expense, cost of electricity per kWh, kWh cost — and they all resolve to the same arithmetic above. What differs is scope. An electricity cost question is usually about one device or one measured block of energy. An electricity expense question is usually about the household total over a month or a year, which means the fixed customer charge, taxes and riders belong in the answer. The tool on this page answers the first question exactly; the electricity bill calculator answers the second by adding a fixed charge and a tax percentage to the same energy figure.

Three habits make either estimate reliable. First, measure rather than assume power: a plug-in meter on a 120 V appliance, or utility interval data for hardwired 240 V equipment, beats any nameplate rating. Second, use runtime, not plugged-in hours, for anything controlled by a thermostat or humidistat. Third, compare like seasons. Twelve months of history tells you far more about an annual electricity expense than one bill multiplied by twelve, because heating, cooling, pool pumps and school schedules all move the number.

Every scenario here is stored in the page URL, so a result can be bookmarked, sent to a contractor or reopened later with the same inputs. Nothing is transmitted to a server for the calculation itself; the arithmetic runs in your browser.

The price of a kilowatt-hour is the single largest driver of household electricity expense, and it varies by more than a factor of three across the country. Each released state guide applies that jurisdiction's 2024 EIA rate and its typical monthly consumption to the same calculations used above, so the numbers stay directly comparable between states. State links are published in measured batches under the site operations plan; the full ranked table covers all 50 states and DC.

ArizonaCaliforniaFloridaGeorgiaIllinoisMichiganNew JerseyNew YorkNorth CarolinaOhioPennsylvaniaTennesseeTexasVirginiaWashington

View the ranked table for all 50 states and DC →

Rates, consumption benchmarks and the watts-to-kilowatt-hours method come from the following published references. Vintages are stated because the underlying tables are revised annually; see our data method for how they are applied.

1. U.S. Energy Information Administration — Electric Power Monthly, Table 5.6.A (2024 annual) — Average residential price per kilowatt-hour for every state and DC.
2. U.S. Energy Information Administration — Form EIA-861 residential sales and customers (2023) — Typical monthly household consumption used in the state benchmarks.
3. U.S. Department of Energy, Energy Saver — Estimating Appliance and Home Electronic Energy Use (2024) — The watts-times-hours-divided-by-1,000 method used by the appliance presets.
4. NIST — Special Publication 811, Guide for the Use of the International System of Units (2008) — Definition of the kilowatt-hour and the energy-unit conversions behind the tool.