Appliance Energy Cost Calculator

See what an appliance really costs to run. Enter watts, hours and your tariff to get kWh and money per day, month and year — with a duty cycle for fridges, AC and heaters.

A 2,000 W heater and a 200 W fridge can cost the same over a month, because the heater runs for two hours and the fridge cycles all day. Pick a preset, adjust the hours and the duty cycle, and the page returns kWh and money per day, month and year.

The appliance

The wattage is on the rating plate or in the manual. For anything with a thermostat — fridge, freezer, air conditioner, water heater — set the duty cycle to the share of time the compressor or element is actually on.

Common appliance Power (W) Hours per day Days per month Duty cycle (%) How many units Electricity rate (per kWh) Currency

Energy per day –

Energy per month –

Energy per year –

Cost per month –

Cost per year –

CO₂ per year –

How this was worked out

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Typical running costs

Appliance	Power	Hours / day	kWh / month	Cost / month

Four rules before you trust the number

The rating plate shows the maximum draw, not the average. A 1,200 W air conditioner does not draw 1,200 W for every minute it is switched on.
Heating and cooling dominate the bill. Water heating, space heating, AC and the dryer are usually the four largest loads in a home.
Standby is small per device but adds up: 5 W across ten devices is 36 kWh a month, roughly the same as a fridge.
Tariffs are tiered in many markets. Use the marginal rate — the price of the next kWh — not the average on the bill.

Practical notes

Measure before you replace. A plug-in energy monitor costs little and settles the argument in a day; the rating plate does not tell you how you actually use the appliance.
For an EV, the charger runs at 7 kW for hours. Charging 40 kWh a week is about the same monthly energy as a small flat.
A heat pump dryer uses roughly half the energy of a condenser dryer for the same load, which matters more than the purchase price over ten years.

Three common mistakes

Multiplying watts by 24 hours for a fridge. The compressor cuts in and out; at a 33% duty cycle the real figure is a third of that.
Using the annual kWh on the energy label as your own figure. The label is measured under a standard test load, not your house.
Forgetting the number of units. Two 1,500 W heaters cost twice as much as the calculator shows for one.