Operating cost
Appliance Energy Cost Calculator
Use this when you know an appliance’s watts and how often you run it. The page annualizes with a disclosed calendar convention and your bill rate.
Numbers stay in this browser. EnergyToolMage does not upload your inputs or require an account.
Formula
kWh/day = W × h/day ÷ 1000; yearly kWh = kWh/day × days/week × (365.25 ÷ 7); cost = kWh × USD/kWh
Assumptions
- Watts are constant while the appliance is on.
- Hours/day cannot exceed 24. Days/week cannot exceed 7.
- Monthly kWh is yearly kWh ÷ 12.
How it works
Daily energy uses the same watts × hours ÷ 1000 identity. Weekly energy multiplies by days/week. Yearly energy multiplies weekly energy by 365.25/7 so leap-year mean length is explicit.
Inputs and results
Inputs: W, hours/day, days/week, USD/kWh. Outputs: kWh and USD for day, week, month, and year.
Worked examples
1500 W heater, 4 hours/day, every day, $0.16/kWh
6 kWh/day. Over 365.25 days that is 2191.5 kWh/year and $350.64/year at the example rate.
How to use this calculator
- Enter nameplate watts.
- Enter hours per day and days per week.
- Enter your electricity rate in USD/kWh.
- Read daily, weekly, monthly, and yearly kWh and dollars.
Limitations
- Cycling appliances (refrigerators, heat pumps) draw less than nameplate on average. Prefer a measured wattage or an EnergyGuide kWh/year.
- Not an energy audit or rebate qualification.
Sources and freshness
- Every rate, wattage, hour, and loss percentage is a user input or a labeled example. Nothing here is a live utility tariff.
- The $0.16/kWh figure that appears in examples is an illustrative default, not a U.S. average and not current.
- Annualization uses 365.25 days per year and 365.25 ÷ 12 days per month. Your billing cycle will differ.
Questions
Where is the wattage?
Look on the nameplate, the manual, or an EnergyGuide label. If the label gives yearly kWh already, the electricity cost calculator is the better page.
What if I only use the appliance a few days a week?
Set days per week. Yearly kWh is daily kWh × days/week × (365.25 ÷ 7).
Can I compare two bulbs here?
For a single appliance, run this form twice. For an old-vs-new lighting wattage, use the LED savings calculator.
Related energy tools
- kWh from wattsKilowatt-hours are power times time. Enter watts or kilowatts and how long the load runs. Optionally price the energy with your own rate.
- Electricity costMultiply energy you already know in kilowatt-hours by the dollars-per-kWh on your bill. Use this when a meter, EnergyGuide label, or another calculator already gave you kWh.
- LED savingsEnter the existing wattage, the replacement wattage, hours per day, and your bill rate. The page prices the yearly energy difference. It is not a second appliance scheduler.