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Appliance Running Cost Calculator

What one device actually costs you a year.

Inputs
W

On the rating plate, or on the plug-in meter.

2

From your bill — the unit rate, not the standing charge.

365
Per year
306.60
Per day
0.84
Per month (average)
25.55
Per hour of use
0.42
Energy used per year
1095 kWh
cost = (watts ÷ 1000) × hours × rate

Anything heating or cooling — kettles, dryers, heaters, ovens — draws roughly a kilowatt or more, which is why those few devices dominate a bill while electronics barely register.

Every tool runs entirely in your browser. Your files are never uploaded to a server.

Divide the watts by 1,000 to get kilowatts, multiply by hours used, then by your price per kWh. A 1,500 W heater run 2 hours a day at 0.28 per kWh costs 0.84 a day, or about 307 a year.

How to use Electricity Cost Calculator

  1. Find the wattage. On the rating plate, in the manual, or measured with a plug-in energy monitor.
  2. Enter your unit rate. From your bill — the price per kWh, not the daily standing charge.
  3. Set the usage. Hours per day and days per year, so seasonal devices are counted honestly.

About calculating electricity running cost

The arithmetic of electricity is simple and the useful part is what it reveals about proportion. Power is measured in watts, energy in kilowatt-hours, and a kilowatt-hour is what a one-kilowatt device consumes in an hour. Divide the watts by a thousand, multiply by the hours it runs, multiply by the price on your bill — that is the whole calculation. Running it across the devices in a house tends to overturn the usual intuition. The things people are told to worry about, chargers and standby lights, draw single-digit watts and cost very little over a year. The things that dominate a bill are the ones that convert electricity into heat: a tumble dryer at 2,500 W, an electric heater at 2,000, a kettle at 3,000, an oven at 2,100. One hour less of a dryer per week saves more than unplugging every charger in the house permanently. Two adjustments make the figure realistic. The rated wattage is normally a maximum, and anything thermostatically controlled — fridges, freezers, heaters, ovens — cycles on and off to maintain a temperature, so its average draw can be half the rating or less. And a bill is not only unit rate: a standing charge applies daily regardless of use, which is why the total here will be lower than the bill and also why it is the more useful number. The standing charge is fixed; the running cost is the part your behaviour changes.

Frequently asked questions

Where do I find an appliance's wattage?
On the rating plate, usually on the back or underside, or in the manual. If it lists volts and amps instead, multiply them. A plug-in energy monitor is more accurate still, because it measures what the device actually draws rather than its maximum.
Why is my calculated total lower than my bill?
Because a bill includes a daily standing charge regardless of usage, and often tax. This works out the running cost of one device, which is the part you can change — the standing charge stays whether you use the appliance or not.
What actually costs the most to run?
Almost always something that heats or cools. Electric heaters, tumble dryers, kettles, ovens and immersion heaters draw a kilowatt or more. A laptop draws around 50 W and a phone charger under 5, so no amount of unplugging chargers matches one hour less of a dryer.
Is standby power worth worrying about?
Individually no, collectively a little. A device drawing 2 W constantly costs a few units of currency a year. Across fifteen devices it becomes noticeable, but it is a much smaller prize than the heating appliances and worth tackling second.
Does a device always draw its rated wattage?
No. The rating is usually the maximum. Anything thermostatically controlled — a fridge, a heater, an oven — cycles on and off to hold a temperature, so real consumption is often half the rating or less. Measuring beats calculating when the difference matters.

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