Enter a device's power, daily usage, and electricity rate to calculate its energy use and cost.
How to Use the Electricity Calculator
Enter the device's power draw in watts, how many hours a day it runs, and how many days — then set the rate you're billed per kWh, since that number varies too much by location and provider to assume one for you. All four fields recalculate the totals immediately.
This is the quick version: one appliance, one question — what's it actually costing me to run this? Plug in a space heater running 3 hours a night for a month, or a window AC unit through a heat wave, and get a straight answer without setting up a full household energy audit.
Daily Energy = Power (W) ÷ 1000 × Hours per Day
Total Energy = Daily Energy × Days
Total Cost = Total Energy × Rate per kWhWatts divided by 1000 converts to kilowatts before multiplying by hours, since utility rates are quoted per kilowatt-hour, not per watt-hour — skip that conversion and the cost comes out a thousand times too high.
Anyone trying to track a whole home's worth of appliances at once — fridge, water heater, lights, everything running in parallel — should reach for this site's dedicated Electricity Bill Calculator instead; this one's built for a single device, not a household total.