How to Use Electricity Cost Calculator
The Electricity Cost Calculator estimates running cost for an appliance from its power draw, use duration and electricity price. It works for a single device or for a repeated usage pattern such as hours per day, week, month or year.
- Enter the appliance wattage — printed on the nameplate.
- Enter usage hours per day, week or month.
- Set price per kWh — check your bill.
- Set the currency symbol — defaults to $.
- Read cost per day and per year with kWh totals.
Formula & Theory — Electricity Cost Calculator
The Electricity Cost Calculator converts watts to kilowatts and normalizes the selected usage period to an average day. From there, daily, monthly and yearly kWh values are linear projections.
kW = power_W / 1000
dailyHours = hours if period = day
dailyHours = hours / 7 if period = week
dailyHours = hours / 30 if period = month
kwhPerDay = kW × dailyHours
costPerDay = kwhPerDay × pricePerKwh
costPerYear = costPerDay × 365Assumptions and Limits
The result uses running watts, not start-up surge. Refrigerators, air conditioners and heaters cycle on and off, so use measured average wattage if possible. Taxes, delivery charges and time-of-use pricing are not included unless you fold them into the entered kWh price.
Use Cases for Electricity Cost Calculator
The Electricity Cost Calculator is useful for:
- Appliance comparisons — Compare an old freezer with an efficient replacement.
- Budget planning — Estimate summer AC, space heater or dehumidifier costs.
- Home audits — Identify large loads before buying smart plugs.
- Shared bills — Estimate one appliance’s fair share in a rental or studio.
For the most reliable number, measure the device with an energy monitor for a representative day and enter that average draw.