Electricity Cost Calculator for Any Appliance
Type in an appliance's wattage, how long it runs and your electricity rate. WattPenny turns that into a cost per hour, day, month and year, so you can see exactly where your bill comes from and what changing your habits would save.
Electricity cost calculator
Estimated cost per month
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Estimates use your rate × energy used. Real bills add fixed fees and taxes, and appliances that cycle (fridges, AC) vary with weather and use.
How the calculator works
Every electricity bill comes down to one unit: the kilowatt-hour, or kWh. Your utility charges a certain number of cents for each one you use. To estimate what a single appliance costs, you need three things: how much power it draws in watts, how many hours it runs, and your price per kWh.
The formula is short. Watts × hours ÷ 1,000 = kWh, then kWh × your rate = cost. A 1,500 watt space heater running 8 hours uses 1,500 × 8 ÷ 1,000 = 12 kWh. At the U.S. average residential rate of 18.34¢ per kWh (June 2026), that day costs $2.20. Run it every day and you are looking at roughly $66.90 a month.
The calculator does that arithmetic for you and adds three practical touches. It has 83 appliance presets with realistic wattages so you do not have to hunt for a label. It has the average rate for every state, so you can get a sensible answer without a bill in front of you. And it handles appliances that cycle on and off, such as refrigerators, by letting you enter the kWh-per-year figure from the yellow EnergyGuide sticker instead of a wattage that would overstate the cost.
Finding your appliance's wattage
- The label. Most appliances have a plate on the back, bottom or plug listing watts (W). Some list amps (A) instead; multiply amps by 120 for a normal US outlet, or by 240 for dryer and EV outlets.
- The EnergyGuide label. Fridges, freezers, dishwashers, washers, water heaters and air conditioners carry a yellow label with estimated kWh per year. Use kWh mode in the calculator for these.
- A plug-in meter. A Kill A Watt style meter costs about $25 and measures the real draw of anything that plugs into a wall outlet. It is the only way to know what an old fridge or a gaming PC actually uses. Our measuring guide walks through it.
What common appliances cost to run
These figures use typical wattages and daily usage patterns at the U.S. average rate of 18.34¢ per kWh. Change any of them in the calculator to match your household.
| Appliance | Watts | Use | kWh / month | Cost / month |
|---|---|---|---|---|
| Space heater (1,500 W) | 1,500 | 8 h × 7 d/wk | 364 kWh | $66.76 |
| Central AC, 3-ton (avg) | 3,500 | 8 h × 7 d/wk | 849 kWh | $156 |
| Window AC, 12,000 BTU (avg) | 1,100 | 8 h × 7 d/wk | 267 kWh | $48.96 |
| Electric water heater (40 gal tank) | 4,500 | 3 h × 7 d/wk | 410 kWh | $75.10 |
| Clothes dryer, electric (per load) | 3,000 | 1 h × 4 d/wk | 52 kWh | $9.54 |
| Refrigerator (modern, 18-22 cu ft) (avg) | 60 | 24 h × 7 d/wk | 44 kWh | $8.01 |
| Refrigerator (older, pre-2005) (avg) | 150 | 24 h × 7 d/wk | 109 kWh | $20.03 |
| EV charger, Level 2 (7.2 kW) | 7,200 | 1.5 h × 7 d/wk | 328 kWh | $60.08 |
| Hot tub (average, incl. heating) (avg) | 400 | 24 h × 7 d/wk | 291 kWh | $53.41 |
| Pool pump, 1.5 HP | 1,500 | 8 h × 7 d/wk | 364 kWh | $66.76 |
| Gaming PC (with monitor) | 450 | 4 h × 7 d/wk | 55 kWh | $10.01 |
| TV, 55 in LED | 80 | 5 h × 7 d/wk | 12 kWh | $2.23 |
| LED bulb (9 W, 60 W equivalent) | 9 | 5 h × 7 d/wk | 1.4 kWh | 25¢ |
| Wi-Fi router + modem | 15 | 24 h × 7 d/wk | 11 kWh | $2.00 |
Two patterns jump out. Anything that makes heat or cold (heaters, AC, water heaters, dryers) dominates the bill, because moving heat takes far more energy than moving electrons through a screen. And the number of hours matters as much as the wattage: a 15 W router that never turns off costs more per month than a 1,500 W kettle used for a few minutes a day.
Why your rate matters more than you think
The same space heater costs four times as much to run in Hawaii as in Nevada. Even within the mainland, a household in Massachusetts or California pays roughly double what one in Louisiana or Nebraska does for identical usage. That is why the calculator asks for your rate instead of assuming one. The full table, with every state ranked, is in our electricity rates by state guide.
Three more things can change the answer for your home:
- Time-of-use pricing. Many utilities now charge two or three times more during late-afternoon peak hours than overnight. If you are on such a plan, when you run the dryer matters. See time-of-use rates explained.
- Tiered pricing. Some utilities raise the per-kWh price once you pass a monthly threshold, so a new appliance may be billed at your highest tier, not your average.
- Fixed charges. Service fees and delivery charges show up regardless of usage. To find your true marginal rate, look at the energy and delivery lines on your bill rather than dividing the total by kWh. Our bill-reading guide shows where to look.
Calculators for specific appliances
Space heater cost
Per hour, per night and per month for 750 W and 1,500 W heaters, plus whether it beats turning up the furnace.
Air conditioner cost
Window, portable, mini-split and central AC costs per day and per month, and what the BTU and SEER numbers mean.
Refrigerator cost
Monthly and yearly running cost for new, old and garage fridges, mini fridges and freezers, plus a replacement payback check.
EV charging cost
Cost per full charge, per mile and per month for your battery size and rate, with a side-by-side against a gas car.
Guides to understanding your bill
How to Read Your Electricity Bill and Find Your Real Rate
Where supply, delivery and fixed charges hide on a US electricity bill, how to work out your true cents-per-kWh rate, and which number to use.
Electricity Rates by State (June 2026 EIA Data)
Every US state ranked by average residential electricity price per kWh, from Nevada at 13.11¢ to Hawaii at 52.72¢, and what the gap means for you.
How Many Watts Do Appliances Use? Full Wattage Chart
Typical wattage, hours of use and monthly cost for 80+ household appliances, from space heaters and AC to fridges, TVs, EV chargers and LED bulbs.
Phantom Load: What Standby Power Really Costs You
How much electricity devices use when they are off, which ones are worth unplugging, the one-watt rule for annual cost, and what to leave alone.
Time-of-Use Electricity Rates: When Power Is Cheapest
How time-of-use electricity plans work, typical peak and off-peak prices, which appliances to shift, and whether a TOU plan would save you money.
The 10 Most Expensive Appliances to Run, Ranked
Ranked by real monthly cost at the US average rate: central AC, water heaters, EV chargers, dryers, hot tubs and old fridges, with one fix for each.
How to Measure What an Appliance Really Uses
Four ways to find an appliance's real electricity use: the label, the EnergyGuide sticker, a $25 plug-in meter and your smart meter's hourly data.
Frequently asked questions
How do I calculate the electricity cost of an appliance?
Multiply the appliance's wattage by the hours it runs, divide by 1,000 to get kilowatt-hours (kWh), then multiply by your electricity rate. A 1,500 W heater running 8 hours uses 12 kWh; at the US average of 18.34¢ per kWh that is about $2.20 a day. The calculator above does this and scales it to a week, month and year.
Where do I find how many watts my appliance uses?
Check the label on the back or bottom of the unit, the power adapter, or the manual. If it only lists amps, multiply by 120 (standard US outlet voltage) to get watts. For appliances that cycle on and off, such as fridges and air conditioners, the yellow EnergyGuide label's kWh per year figure is more accurate than the wattage; switch the calculator to kWh mode and enter it.
What electricity rate should I use?
The best number is on your own bill; divide the total amount due by the kWh used that month to get your true all-in rate. If you do not have a bill handy, pick your state in the calculator to use the June 2026 average from the U.S. Energy Information Administration. The national average is 18.34¢ per kWh.
Why is my real bill higher than the calculator says?
The calculator estimates the energy charge only. Utilities also add fixed monthly service fees, delivery charges, taxes and sometimes demand charges or tiered pricing that raises the rate once you pass a usage threshold. Appliances that cycle, like AC and fridges, also run harder in extreme weather than a typical average suggests.
Does the calculator work for 240 V appliances like dryers and EV chargers?
Yes. Cost depends on watts, not volts. A 240 V dryer rated at 3,000 W costs exactly the same to run as a 120 V appliance drawing 3,000 W. If the label lists amps at 240 V, multiply by 240 to get watts.
Is 1 kWh the same as 1,000 watts?
Not quite. A watt measures power, the rate of energy use. A kilowatt-hour measures energy, power multiplied by time. 1,000 watts running for one hour is 1 kWh; 100 watts running for ten hours is also 1 kWh. Your utility bills you per kWh.
Is my data stored or sent anywhere?
No. The calculator runs entirely in your browser. Nothing you type is sent to a server or stored, apart from your light or dark mode preference. See the privacy policy for details on cookies used by advertising.