Electricity Cost Calculator
See what an appliance costs to run per day, month, and year from its wattage, daily hours, and your price per kWh.
Monthly figures use an average 30.44-day month. To find your price per kWh, divide a recent bill's total energy charge by the kilowatt-hours you used that period.
How it works
Every electrical device draws a certain number of watts. Multiply that by the hours it runs and you get watt-hours; divide by 1,000 and you have kilowatt-hours, the unit your utility actually bills you for.
The calculator turns your inputs into daily energy use, then scales it to a month (using an average 30.44-day month) and a full year, and multiplies each by your price per kWh to show the cost.
A quick sanity check: a 1,000-watt space heater running three hours a day uses 3 kWh, which at 15 cents costs about 45 cents a day — roughly 164 dollars over a year of daily use.
Frequently asked questions
How do I find my price per kWh?
Look at a recent electricity bill. Divide the total energy charge for the period by the number of kilowatt-hours you used. In the US this is often somewhere around 12 to 20 cents, but it varies widely by state and plan.
Where do I find an appliance's wattage?
Check the label on the device or its power brick, or the manual. If only amps and volts are listed, multiply them (amps × volts) to get watts. Many appliances also list a typical wattage online.
Does this account for appliances that cycle on and off?
Not directly. Things like fridges and air conditioners only draw full power part of the time. For those, estimate the equivalent hours they run at full wattage, or use the yearly kWh from the label if provided.