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Electricity Cost Calculator

Free electricity cost calculator: see what any appliance costs to run from its watts, hours used and your kWh price — per hour, day, month and year.

YOUR WORKSPACEFree to use. No sign-up.

Appliance power

Power unit

Hours used per day

Number of days

Electricity price ($/kWh)

—

Enter your appliance details above.

Assumes a flat rate. Utilities often add delivery charges, taxes or time-of-use pricing — divide your bill's total by its kWh to get the effective $/kWh, which is usually higher than the base rate. Nameplate wattage is the maximum draw, so thermostatic appliances (fridges, heaters) average lower than this.

Deep dive guides

A LITTLE CONTEXT · 4 MIN READElectricity and Fuel: Where Your Running Costs Come From

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Electricity and Fuel: Where Your Running Costs Come From — The usage × price formula behind electricity and fuel running costs: kilowatt-hours, mpg in the denominator, cost per hour, cost per mile, and where savings hide.
Power Units Explained: Watts, Horsepower and BTU per Hour — Watts, horsepower, PS, BTU/h and tons of refrigeration are one quantity at different scales — here are the exchange rates and where each unit fits.
The Subscription Audit: Finding the Money Hiding in Recurring Charges — Why mixed billing cycles hide your true subscription total, and how to normalize and rank it.
BTU by the Numbers: Sizing Heating and Cooling for One Room — The 20 BTU per square foot rule, its correction factors for sun, insulation, and people, and why oversized air conditioners misbehave.
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Ohm's Law Explained: V = IR and the Power Wheel — How voltage, current, resistance and power lock together through two small equations — and why any two values give you the other two.

How electricity cost calculator works

This calculator turns an appliance's power draw into a dollar cost. Enter the power rating (watts or kilowatts), how many hours a day it runs, how many days you want to project, and your electricity price per kWh.

Energy in kilowatt-hours is power in kilowatts times hours. kWh per day = (watts divided by 1000) times hours per day; total kWh = that times the number of days. Cost is kWh times your price per kWh. Cost per hour is simply kilowatts times the kWh price.

The result shows kWh per day, total kWh, cost per hour, cost per day, the total over the period, plus a 30-day monthly and 365-day annual figure so you can compare an appliance to your whole bill. Use the nameplate wattage on the device for accuracy.

Frequently asked questions

How do I calculate the cost to run an appliance?

Multiply the appliance's wattage by the hours used and divide by 1000 to get kWh, then multiply by your electricity price per kWh. This calculator does that and also rolls it up to daily, monthly and annual costs.

Where do I find the wattage of my appliance?

Check the sticker or nameplate on the back or bottom, or the manual. Many devices list watts directly; some list amps and volts, in which case watts = amps times volts. For variable devices like a fridge, use the average or the annual kWh on the EnergyGuide label.

What is a kWh and what should I enter for the price?

A kilowatt-hour is 1000 watts running for one hour, the unit your electricity bill is charged in. Enter your price per kWh from your bill (the supply plus delivery charges). The US average is around $0.16/kWh but varies by state and provider.

Does this account for standby or vampire power?

Only if you enter the standby wattage and the standby hours. Many devices draw a few watts even when off. To capture that, run the calculator twice (active and standby) and add the costs, or average the wattage over the day.

Electricity Cost Calculator

Deep dive guides

How electricity cost calculator works

Frequently asked questions

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