What this calculator does
The Electricity Cost Calculator estimates how much it costs to run a specific appliance or device, such as an air conditioner, space heater, or TV, based on its power rating and how often you use it.
How the calculation works
Power in watts is converted to kilowatt-hours (kWh), the unit electricity is billed in, using the formula: (watts × hours used per day) ÷ 1000. That daily energy use is then multiplied by the number of days used per month, and by your electricity rate, to estimate monthly cost. Yearly cost simply extends the monthly estimate across 12 months.
This is a general estimate for planning and comparison purposes. Actual electricity bills also include fixed charges, taxes, tiered pricing, and other appliances running at the same time, and real appliance power draw can vary from the rating printed on the device.