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Electricity cost calculator
Type the watts on the rating plate and the hours of use: the cost per hour, month and year shows at your state’s average price.
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Cost to run it in Texas
$28.91 a month
$347 a year · 180.0 kWh a month
| Per hour of use | $0.24 |
| Per day | $0.96 |
| Per month | $28.91 |
| Per year | $347 |
Watts × hours ÷ 1,000 = kWh, times the price. Appliances with a thermostat or compressor (heaters, fridges, AC) draw full power only part of the time, so real use is often lower. How this is calculated.
Running a 1,500-watt appliance four hours a day costs $28.91 a month in Texas, where homes paid an average 16.06¢ per kWh in January to July 2026, and $83.30 in Hawaii, the most expensive state at 46.28¢. The arithmetic is short: watts times hours of use, divided by 1,000, gives kilowatt-hours, and kilowatt-hours times the price per kWh gives dollars. Those four hours a day for 30 days come to 180 kWh. The calculator fills in your state's average residential price from the Energy Information Administration, which divides what utilities billed households by the electricity they sold, so delivery charges and fixed monthly fees are spread into the figure. The national average was 18.19¢, against 16.48¢ for 2024 as a whole. Appliances with a thermostat or a compressor draw their full rated power only part of the time, so their real cost is usually lower than the label suggests.
Watts, kilowatt-hours and the price on your bill
A watt measures how fast a device draws power at a given moment. A kilowatt-hour is 1,000 watts drawn for one hour, and it is the unit your utility bills. A 1,500 W device running for one hour uses 1.5 kWh; a 10 W device would need 150 hours to use the same amount. Once you have kWh, the bill follows from your price. At the U.S. average of 18.19¢, each kWh costs about $0.18, so 1,000 W for one hour costs the same.
The calculator multiplies the watts you enter by hours per day and days per month, divides by 1,000, and multiplies by the price. With its defaults, 1,500 W for 4 hours over 30 days in Texas, that is 180 kWh and $28.91 a month, $347 a year, or $0.24 per hour of use.
| Power | Per hour, North Dakota | Per hour, U.S. average | Per hour, Hawaii | Per month at 4 h a day, U.S. |
|---|---|---|---|---|
| 10 W | $0.00 | $0.00 | $0.00 | $0.22 |
| 100 W | $0.01 | $0.02 | $0.05 | $2.18 |
| 500 W | $0.06 | $0.09 | $0.23 | $10.91 |
| 1,000 W | $0.12 | $0.18 | $0.46 | $21.83 |
| 1,500 W | $0.19 | $0.27 | $0.69 | $32.74 |
| 3,000 W | $0.37 | $0.55 | $1.39 | $65.48 |
| 5,000 W | $0.62 | $0.91 | $2.31 | $109.14 |
Finding the real wattage
The rating plate, usually on the back or bottom of the device or inside the door, gives either watts or volts and amps. Multiply volts by amps when watts are missing: a plate reading 120 V and 10 A means a maximum of 1,200 W. That maximum is the ceiling, not the average. A refrigerator, a window air conditioner, a space heater with a thermostat or an electric oven cycles on and off to hold a temperature, so over an hour it may draw full power for twenty minutes or for fifty. A plug-in energy meter measures actual kWh over a few days and removes the guesswork.
Duty cycle in practice
If a 1,500 W heater holds a room at temperature by running half the time, enter 2 hours instead of 4: the monthly cost at the U.S. average falls from $32.74 to $16.37. Devices that never switch off work the other way. A 10 W standby draw around the clock adds 7.2 kWh and $1.31 a month, small alone, noticeable when a home has a dozen of them.
Where a kWh costs the most and the least
The five cheapest states in January to July 2026 were North Dakota, Nebraska, Idaho, Utah and Louisiana; the five most expensive were Hawaii, California, Massachusetts, Maine and New York, according to the EIA Electric Power Monthly. The same 1,500 W used four hours a day costs $22.25 a month in North Dakota and $83.30 in Hawaii. The calculator lets you overwrite the state average with the rate on your own bill, which is the better choice if your utility uses tiers, time-of-use pricing or a large fixed customer charge.
Why your rate may differ from the state average
The EIA average blends every residential customer in the state, cities and rural cooperatives alike, and spreads fixed monthly fees into the per-kWh price. A household that uses little electricity sees those fees weigh more per kWh; a large user sees them weigh less. On a time-of-use plan, the same appliance costs more in the late afternoon than overnight, so shifting a dryer or a dishwasher can matter more than replacing it. To see how all your devices add up to a month, the electric bill calculator starts from total kWh, and the EV charging calculator handles the largest new load many homes add.