Find out how much it costs to run an appliance. Enter its wattage, how long you use it and your electricity rate, and see the cost per day, month and year.
Last updated: October 2, 2026
Appliances with thermostats or compressors (heaters, fridges, AC) cycle on and off, so real use is often lower than the rated wattage × hours.
How the calculation works
kWh per day = watts × hours per day ÷ 1,000
cost per day = kWh per day × rate per kWh
cost per month = cost per day × days used per monthYour utility bills you per kilowatt-hour (kWh): using 1,000 watts for one hour. Your rate is printed on your electric bill; some plans charge different rates at different times of day, so use the rate for when the appliance actually runs.
Where to find the wattage
- On the nameplate or label, usually on the back or bottom.
- If only amps are listed: watts ≈ volts × amps (for example, 120 V × 10 A = 1,200 W).
- For the most accurate figure, use a plug-in energy meter for a few days.
Frequently asked questions
Why is my real bill different?
Bills include fixed charges, delivery fees and taxes, and many appliances don’t draw full power all the time. This calculator estimates the energy cost of one appliance.
Do devices use power when turned off?
Many do, in standby mode. The amounts are small per device but add up. A power strip you switch off can help.