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Electricity Cost Calculator

Estimate what any appliance adds to your electric bill. Replace the sample inputs with numbers from the appliance label and your utility bill.

Your inputs

Calculate operating cost

watts
hours
days
$/kWh
EIA residential average price, not a utility-specific rate. Your bill’s all-in rate gives the best personal estimate.

Live estimate

Estimated monthly cost$33.19at 18.44¢ per kWh
Per day$1.11
Per year$404
Monthly use180.0 kWh
Transparent calculation(1500 W ÷ 1,000) × 4 hr × 30 days × $0.184/kWh

Actual use can differ when equipment cycles or changes power. Measure at the wall when precision matters.

How to calculate electricity cost

First, convert watts to kilowatts by dividing by 1,000. Multiply that number by hours of use to get kilowatt-hours (kWh). Then multiply kWh by the price you pay for each kWh.

watts ÷ 1,000 × hours used × electricity rate = cost

Where to find the right numbers

Appliance wattage

Check the nameplate, power adapter, owner’s manual, or manufacturer specification page. If a device lists amps rather than watts, multiply volts by amps for a rough maximum wattage.

Your electricity rate

For an all-in estimate, divide the total electric charges on your latest bill by the total kWh used. This captures more of the costs you actually pay than a generic average.

Why the real cost can differ

Heating and cooling equipment, refrigerators, and many motors cycle instead of running at full power continuously. Seasonal weather, standby use, time-of-use pricing, taxes, and fixed fees can also change the final bill.

Common appliance cost examples

These starting examples use the latest 2026-05 U.S. residential average of 18.44¢/kWh. They are transparent comparisons, not claims about a specific product.

Appliance exampleMonthly useMonthly cost
Wi-Fi router12 W · 24 hr/day8.6 kWh$1.59
Gaming PC500 W · 4 hr/day60.0 kWh$11.06
Space heater1,500 W · 4 hr/day180.0 kWh$33.19
Electric dryer3,000 W · 0.75 hr/day45.0 kWh$8.30

Choose the calculator for the question

Space heater cost by wattageCalculate →Air-conditioner operating costCalculate →Gaming PC cost scenariosOpen →Wi-Fi router monthly costOpen →

Frequently asked questions

How do I calculate electricity cost from watts?

Divide watts by 1,000, multiply by operating hours, then multiply by the electricity price in dollars per kWh. Multiply by days of use for a monthly estimate.

What electricity price should I enter?

Use the variable price that applies to added usage for a new appliance estimate. To explain a completed bill, divide current electric charges by billed kWh for an all-in historical price.

Does appliance wattage equal actual electricity use?

Not always. Nameplate wattage may be a maximum. Heating, cooling, refrigeration, motors, and computers can cycle or vary power, so measured kWh produces a better estimate.

Data source

U.S. Energy Information Administration, Electricity Retail Sales, residential average price. Latest monthly data: 2026-05; comparison baseline: 2025 annual. Verified 2026-08-05. Monthly prices can vary seasonally and are not utility-specific rates.

View EIA data