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Electricity Cost Calculator

Updated June 2026 · By the NumberBench editorial team · How we calculate

See what a device really costs to run. Enter its wattage, how long it runs, and your electricity rate to get daily, monthly, and yearly cost.

watts
hrs
$/kWh
days
Cost for the period—
Cost per day—
Cost per year—
Energy per day—

Cost: day / month / year

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Reading your usage

Electricity is billed per kilowatt-hour (kWh) — 1,000 watts running for one hour. Find the wattage on the appliance label or nameplate, and your rate on your utility bill. Heaters, dryers, and AC units dominate bills because they pull thousands of watts; small electronics cost little even running all day.

How it’s calculated

kWh per day = watts × hours ÷ 1000. Cost = kWh × rate; period and annual scale by days and 365.

Results update as you type and are estimates, not professional advice — verify important decisions with a qualified professional.

Worked example

A 1,000-watt device run 5 hours a day at $0.17/kWh costs about $0.85/day, ~$310/year.

Common mistakes

  • Using amps as watts (multiply amps by volts).
  • Forgetting always-on standby power.

Where it is used

  • Finding what an appliance costs to run.
  • Deciding whether to replace an energy hog.

Frequently asked questions

Where do I find the wattage?

On the appliance's label or manual. If only amps are listed, multiply amps by volts (usually 120) to get watts.

What's a typical rate?

U.S. residential rates vary widely by state. Use the price per kWh printed on your latest bill for accuracy.

Does standby power count?

Yes — many devices draw a few watts even when off. For always-on devices, set hours to 24.