kWh / electricity cost calculator

Find out what an appliance actually costs to run — enter its wattage, hours of use, and your electricity rate to get daily, monthly, and yearly cost.

Wattagei
W
Hours used per day
Rate per kWh
$
Result
Cost per month$21.60
kWh per month135.0
Cost per year$259.20

Estimate only — actual rates often include fees and tiered pricing.

How electricity cost is calculated

Divide wattage by 1,000 to get kilowatts, multiply by hours used per day for daily kWh, then by 30 for a monthly estimate. Multiply kWh by your utility's rate per kWh (check a recent bill) to get cost — a 1,500 W space heater run 3 hours a day costs about $21.60 a month at 16¢/kWh.

Frequently asked questions

Check a recent utility bill for your rate per kWh — it's often listed as "energy charge" or "supply rate." The US average is around 16¢/kWh, but rates vary widely by region and season.

It depends on wattage and hours of use — a low-wattage device run briefly costs pennies, while a high-wattage appliance like an electric dryer or space heater run for hours can add up quickly. Enter your appliance's numbers above for a specific answer.