Electricity Cost Calculator
This electricity cost calculator estimates what an appliance costs to run per day, month, and year from watts or amps times volts, hours per day, and your price per kWh.
How to use
- Choose watts, or amps times volts. A preset fills typical wattage and hours per day.
- Enter hours per day (0 to 24) and the price per kWh from your utility bill.
- Read kWh and cost per hour, day, month, and year. A month is 30 days and a year is 365.
- Turn on compare to place a second device beside the first at the same rate.
Formula
Kilowatt-hours equal watts times hours divided by 1,000. If the label lists amps, watts equal amps times volts. Cost equals kWh times your price per kWh. Daily use cannot exceed 24 hours. Monthly totals use 30 days and yearly totals use 365 days.
Example. A 1,500-watt space heater used 4 hours a day at $0.16 per kWh uses 6 kWh a day. That is $0.24 an hour, $0.96 a day, $28.80 a month, and $350.40 a year.
Example. Ten amps at 120 volts is 1,200 watts. One hour a day at $0.10 per kWh is 1.2 kWh and $0.12 a day, $3.60 a month, and $43.80 a year.
Estimate, not a bill
Nameplate watts are often higher than average draw, and a refrigerator cycles on and off. Utility bills add fees, taxes, and tiered rates this page does not include. Presets are typical starting points, not a measurement of your device.
Frequently asked questions
How do I calculate electricity cost?
Watts x hours used / 1,000 = kWh. Multiply kWh by your price per kWh.
Where do I find my price per kWh?
On your utility bill. Divide the energy charge by the kWh used, or use the listed rate.
What is a kilowatt-hour?
The energy used by 1,000 watts running for one hour.
How do I find an appliance's wattage?
Check the label or manual. If it lists amps, multiply amps by volts.
Are the results exact?
No. Devices often draw less than their rated watts, and bills add fees and taxes.
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