Electricity Cost Calculator
- Updated
- Formula shown
- Free, no sign-up
Results
1,000 W for 2 h a day, 365 days a year: 730 kWh a year
| Appliance | Typical watts | kWh per year |
|---|---|---|
| Coffee maker | 900–1,200 | 657–876 |
| Clothes washer | 350–500 | 255–365 |
| Clothes dryer | 1,800–5,000 | 1,314–3,650 |
| Dishwasher | 1,200–2,400 | 876–1,752 |
| Dehumidifier | 785 | 573 |
| Hair dryer | 1,200–1,875 | 876–1,369 |
| Portable heater | 750–1,500 | 548–1,095 |
| Clothes iron | 1,000–1,800 | 730–1,314 |
Nameplate wattage is the most an appliance draws. Many use less on average: refrigerators cycle on and off, and heaters and air conditioners run with thermostats. A plug-in energy meter shows the real figure.
How to use the electricity cost calculator
- Find the appliance's wattage on its label or nameplate. If only volts and amps are listed, switch to Volts and amps.
- Enter how many hours a day it runs and on how many days a year: 365 for everyday items, fewer for a seasonal fan or heater.
- Add any standby power if the appliance draws power while switched off.
- Enter your price per kWh from your electricity bill to see the cost. The table compares typical appliances at the same hours.
Electricity usage formula
Annual kWh = daily kWh × days used per year
Annual cost = annual kWh × price per kWh · Monthly = annual ÷ 12
Watts = volts × amps (when the wattage isn't listed)
A kilowatt-hour (kWh) is 1,000 watts used for one hour, the unit on your electricity bill. This is the method the US Department of Energy's Energy Saver guidance describes, as reproduced in the Virginia Cooperative Extension fact sheet "Estimating Appliance and Home Electronic Energy Use". The same fact sheet points out that a refrigerator, although always plugged in, runs only part of the time: divide the hours it is plugged in by three to estimate the hours at full wattage.
Worked examples
The fact sheet's own example is a 200 W window fan used 4 hours a day for 120 days: 200 × 4 × 120 ÷ 1,000 = 96 kWh a year, which at its example rate of 8.5¢ per kWh costs $8.16. A 1,500 W portable heater run 4 hours a day for 90 winter days uses 540 kWh; at an example price of $0.15 per kWh that is $81.00 for the season. By the one-third rule, a refrigerator with a 725 W nameplate uses up to about 2,117 kWh a year; for a new model, the yearly kWh on its yellow EnergyGuide label, measured in a standard test, is a better figure. Even a 5 W standby load adds up to 43.8 kWh a year.
Typical appliance wattages
Typical nameplate wattages from the Virginia Cooperative Extension list based on DOE guidance (BSE-301NP, 2020). Your own appliance may differ; its label is the best source.
| Appliance | Typical watts | kWh per hour of use | kWh a year at 1 hour a day |
|---|---|---|---|
| Coffee maker | 900–1,200 | 0.9–1.2 | 329–438 |
| Clothes washer | 350–500 | 0.35–0.5 | 128–183 |
| Clothes dryer | 1,800–5,000 | 1.8–5 | 657–1,825 |
| Dishwasher (the drying feature greatly increases use) | 1,200–2,400 | 1.2–2.4 | 438–876 |
| Dehumidifier | 785 | 0.785 | 287 |
| Hair dryer | 1,200–1,875 | 1.2–1.875 | 438–684 |
| Portable heater | 750–1,500 | 0.75–1.5 | 274–548 |
| Clothes iron | 1,000–1,800 | 1–1.8 | 365–657 |
| Microwave oven | 750–1,100 | 0.75–1.1 | 274–402 |
| Ceiling fan | 65–175 | 0.065–0.175 | 24–64 |
| Window fan | 55–250 | 0.055–0.25 | 20–91 |
| Laptop computer | 50 | 0.05 | 18 |
| Refrigerator (frost-free, 16 ft³) (cycles on and off: divide plugged-in hours by three) | 725 | 0.725 | 265 |
| Flat-screen TV | 120 | 0.12 | 44 |
| Toaster | 800–1,400 | 0.8–1.4 | 292–511 |
| Toaster oven | 1,225 | 1.225 | 447 |
| Vacuum cleaner | 1,000–1,440 | 1–1.44 | 365–526 |
| Water heater (40 gallon) | 4,500–5,500 | 4.5–5.5 | 1,643–2,008 |
| Water pump (deep well) | 250–1,100 | 0.25–1.1 | 91–402 |
Tips for cutting appliance costs
- Heat is expensive. Heaters, dryers, water heaters, irons and toasters have the highest wattages, so the hours they run matter most.
- Watch the always-on loads. Small standby draws run 8,760 hours a year. A power strip with a switch cuts them completely.
- Measure instead of guessing. A plug-in usage monitor shows the real kWh for 120 V devices; it can't be used on large 240 V appliances such as dryers and water heaters.
- Leave wiring to a professional. Adding circuits or hard-wiring appliances is electrical work: it must follow your local code and be done by a qualified person where required.
- Use your full rate. Divide the total on your bill by the kWh used to get an all-in price that includes delivery charges.
Sizing a new air conditioner? Try the BTU calculator. For circuits and wiring, see the Ohm's law calculator and the voltage drop calculator.
Frequently asked questions
How do I calculate the cost of running an appliance?
Multiply the wattage by the hours used per day and divide by 1,000 to get kWh per day, then multiply by your price per kWh. A 1,000 W appliance used 2 hours a day uses 2 kWh a day, or 730 kWh a year; at an example price of $0.15 per kWh that costs $0.30 a day and $109.50 a year.
How many kWh does a 1,500 W heater use?
A 1,500 W heater uses 1.5 kWh for every hour it runs at full power. Four hours a day is 6 kWh a day, and 90 days of that is 540 kWh. A thermostat that cycles the heater off part of the time lowers the real figure.
How do I convert amps to watts?
Multiply the amps by the voltage: watts = volts × amps. An appliance drawing 12.5 A at 120 V uses up to 1,500 W. For motors and other AC loads this gives the apparent power, so the true wattage can be somewhat lower.
What is a kilowatt-hour?
A kilowatt-hour (kWh) is the energy used by a 1,000 W load running for one hour, or a 100 W load for 10 hours. It is the unit your electricity company bills you in, so the cost of any appliance is its kWh multiplied by your price per kWh.
How much does standby power cost?
Standby loads run all year, 8,760 hours. A device that draws 5 W while switched off uses 5 × 8,760 ÷ 1,000 = 43.8 kWh a year. Multiply by your price per kWh to see the cost; a switched power strip removes it completely.