What this tool helps you find
Enter the appliance wattage, daily hours of use, and your price per kilowatt-hour. The estimate scales one day of use to a 30-day month and a 365-day year.
Formula
Energy (kWh) = watts × hours ÷ 1,000. Cost = energy × price per kWh.
Worked example
A 100 W lamp used 5 hours uses 0.5 kWh per day.
Common mistake
Use the appliance’s running wattage, not its voltage or monthly kWh label. The result estimates energy charges only and excludes fixed fees and taxes.
When to use it
Compare the running cost of appliances or estimate the bill impact of using a device for extra hours.
Questions and answers
What is a kilowatt-hour?
A kilowatt-hour is the energy used by a 1,000-watt device running for one hour.
Does the result include fixed utility fees?
No. It estimates usage charges only using the rate you enter.