Always-on device and smart plug running cost

Work out how much a device costs when it stays plugged in, whether it is a charger, a box, a speaker or a smart plug of its own. Enter its power, the hours per day it draws that power and the price you pay per kWh.

The real power of a device is read on a plug with energy metering or on a wattmeter. The price per kWh is on your electricity bill.

Enter your values, then calculate.

Method and limitations

Energy per year in kWh = power in watts × hours per day × 365 ÷ 1000. Cost per year = energy per year × price per kWh. Cost per month = cost per year ÷ 12. Energy is shown to one decimal place and costs to two. Every value comes from you: the tool assumes no power, no hours and no price.

Sources

No external reference is documented for this calculation; its method and limitations are described above.