How do I calculate the cost of running an appliance?

Watts times hours used, divided by 1,000, times your rate per kilowatt-hour. A 1,500 W heater for six hours is 9 kWh a day, which at 17 cents is about $1.53.

What uses the most electricity in a home?

Heating and cooling, then water heating, then anything else with a heating element — dryer, oven, kettle. Electronics and lighting are usually a small fraction by comparison.

Does leaving things on standby cost much?

Individually, very little — a few watts each. Collectively across a whole house it typically adds up to 5 to 10 percent of a bill, which is real but far less than a single space heater.

Why is my actual bill higher than this estimate?

Because a bill includes standing charges, taxes and often tiered rates that rise above a usage threshold. This calculates the energy cost of one appliance, not the whole bill.

Do appliances use their full rated wattage?

Only those with heating elements. Anything with a compressor — fridge, freezer, air conditioner — cycles on and off and averages roughly a third of its rating over a day.

Electricity Cost Calculator

What an appliance costs to run per day, month and year at your electricity rate.

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About the Electricity Cost Calculator

Cost is watts times hours divided by 1,000, times your rate per kilowatt-hour — because the kilowatt-hour is the only unit an electricity bill is actually charged in. A 1,500 W heater running six hours a day uses 9 kWh, which at 17 cents is about $1.53 a day and $559 a year.

Nameplate wattage is the maximum draw, not the average. Anything that cycles — a fridge, a freezer, an air conditioner — runs its compressor perhaps a third of the time, so its real consumption is well below the rating.

Anything with a heating element is the opposite: a kettle, a dryer, an oven or a space heater draws close to its full rating for the entire time it is on. That is why a handful of appliances dominate a bill while a dozen low-power devices barely register.

How it works

Pick an appliance or type in its wattage.
Set how many hours a day it runs and your rate per kWh.
You get the cost per day, month and year, and the energy used.

Frequently asked questions

How do I calculate the cost of running an appliance?: Watts times hours used, divided by 1,000, times your rate per kilowatt-hour. A 1,500 W heater for six hours is 9 kWh a day, which at 17 cents is about $1.53.
What uses the most electricity in a home?: Heating and cooling, then water heating, then anything else with a heating element — dryer, oven, kettle. Electronics and lighting are usually a small fraction by comparison.
Does leaving things on standby cost much?: Individually, very little — a few watts each. Collectively across a whole house it typically adds up to 5 to 10 percent of a bill, which is real but far less than a single space heater.
Why is my actual bill higher than this estimate?: Because a bill includes standing charges, taxes and often tiered rates that rise above a usage threshold. This calculates the energy cost of one appliance, not the whole bill.
Do appliances use their full rated wattage?: Only those with heating elements. Anything with a compressor — fridge, freezer, air conditioner — cycles on and off and averages roughly a third of its rating over a day.

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