Appliance Energy Cost Calculator
See what any device costs to run per day, month, and year based on its wattage and your electricity rate.
This calculator runs entirely in your browser. Nothing you type is uploaded or stored.
How to use this tool
This appliance energy cost calculator turns electricity wattage pricing into clear numbers you can act on. Follow these steps:
- Find the wattage of your appliance. It is usually printed on a label on the device, on its power brick, or in the manual. Enter that value in the watts field.
- Estimate how many hours you actually run it each day. For something like a refrigerator that cycles on and off, use the average running hours, not 24.
- Enter your electricity rate in dollars per kilowatt hour. You will find this on your power bill, often listed as the price per kWh. The US average sits around 0.17 dollars per kWh, which is the default here.
- If you have more than one of the same device, set the number of units so the totals scale up.
- Press Calculate cost to see the kilowatt hour cost broken down into daily, monthly, and yearly figures, then copy the result if you want to save it.
The formula
Daily cost = kWh per day × rate per kWh
Monthly cost = daily cost × 30
Yearly cost = daily cost × 365
Wattage tells you how much power a device draws at any moment. Multiply that by the hours you use it to get watt hours, then divide by 1000 to convert to kilowatt hours, the unit your utility bills you in. Multiplying kilowatt hours by your rate gives the cost, and this device usage tracker simply scales that daily figure to a month and a year. Months use 30 days and years use 365 days so the numbers stay easy to compare.
A real example
Say you run a 1200 watt window air conditioner for 6 hours a day and pay 0.17 dollars per kWh. First, 1200 multiplied by 6 is 7200 watt hours, which divided by 1000 is 7.2 kWh per day. At 0.17 dollars, that is about 1.22 dollars a day. Over a 30 day month that is roughly 36.72 dollars, and across a full year it adds up to around 446.76 dollars. Seeing the yearly number is often what convinces people that a more efficient unit pays for itself.
Common questions
Where do I find the wattage of my appliance?
Check the rating label on the back or bottom of the device, the power adapter, or the user manual. If only amps and volts are listed, multiply them together to get watts. For example, 5 amps at 120 volts is 600 watts.
What electricity rate should I use?
Use the price per kilowatt hour from your most recent power bill, since rates vary widely by state and provider. The default of 0.17 dollars per kWh is a rough US average and is only a starting point.
Why are appliances like fridges hard to estimate?
Devices with a thermostat or motor cycle on and off, so they do not draw full power all day. Enter the average number of hours they actually run rather than the full 24, or you will overstate the cost.
Does this account for standby or phantom power?
No. This tool uses the running wattage you enter. Many devices also draw a small amount in standby, so real bills can be slightly higher. You can model standby separately by entering its low wattage and 24 hours.
How accurate are these numbers?
They are good estimates for planning and comparison, not exact billing figures. Actual cost depends on real usage, tiered or time-of-use rates, taxes, and fees. Treat the results as educational guidance, not a guaranteed bill amount.