Utility Cost Calculator

Find out what an appliance costs to run per hour, per month and per year using your own electricity rate.

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Enter your numbers

Printed on the label or in the manual. A space heater is often 1,500 W.

Find it on your bill: total charges ÷ kWh used. The default is only an example.

Your results will appear here as you type.

How this is calculated

kWh per month = Watts × Hours per day × Days ÷ 1,000 × Quantity. Cost = kWh × Your rate. Real usage varies: thermostats and compressors cycle on and off, so many appliances draw full power only part of the time.

Assumptions

  • Assumes the appliance draws its full rated wattage while on. Many appliances cycle, so real costs are often lower. Use the all-in rate from your own bill.

Sources

Estimates for planning and education only. Not financial, tax or legal advice, and not an official government calculation. Calculations run in your browser; nothing you enter is stored or sent.

Find your real electricity rate

Your rate is on your bill. The simplest way to get an all-in number is to divide the total electricity charges by the kilowatt-hours (kWh) you used that month. This includes delivery charges and fees, which a “supply rate” alone leaves out. Rates vary a lot by state and utility, so the default in the calculator is only an example.

Find the appliance wattage

Look for the label on the back or bottom of the appliance, or check the manual. If it lists amps instead of watts, multiply amps by volts (120 V for most US outlets). For appliances that cycle on and off, like refrigerators, the label wattage overstates real use; a plug-in electricity monitor gives the most accurate number.

Example

A 1,500 W space heater running 5 hours a day for 30 days uses 1.5 kW × 5 × 30 = 225 kWh. At $0.17 per kWh, that is $38.25 a month.

See more ways to cut the bill in how to lower your monthly bills.

Frequently asked questions

What is a kilowatt-hour?

A kilowatt-hour is the energy used by something drawing 1,000 watts for one hour. A 100 W device running for 10 hours also uses 1 kWh.

Does unplugging devices really save money?

For devices with standby power, such as game consoles, set-top boxes and chargers, a little. Unplugging or using a smart power strip on an entertainment center can trim a few dollars a month; heating, cooling and water heating are where the big savings are.

Sources

  1. U.S. Energy Information Administration — Electric Power Monthly (average prices by state) (opens in a new tab)

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