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.
