Appliance Running Cost Calculator
What an appliance costs to run — per hour, day, month and year — from its wattage and your tariff.
Energy is power multiplied by time.
How the appliance running cost calculator works
Energy is power multiplied by time. A 2,000 W heater running for three hours uses 6 kWh, and the cost is that times your rate.
The figure that surprises people is the annual one. A device drawing a trivial 5 W continuously uses 43.8 kWh a year, which is more than a washing machine used weekly. Small constant loads beat large occasional ones, and that is the whole argument for looking at standby power.
Wattage is on the appliance label or in its manual. Where a range is given, the higher figure is the draw when actively working; heating and cooling appliances cycle, so their average is well below their rating.
Formula: cost = watts / 1000 × hours × rate
Worked examples
| Inputs | Cost per year | Note |
|---|---|---|
| A 2 kW heater, three hours a day | $701.27 | about 1,000 a year |
| A 5 W device left on permanently | $14.03 | 43.8 kWh a year |
| A TV with real standby draw | $91.17 | standby is a third of it |
FAQFrequently asked questions
How do I work out what an appliance costs to run?
Divide its watts by 1,000 to get kilowatts, multiply by hours used, then by your rate per kilowatt-hour.
Where do I find my electricity rate?
On a recent bill, as the usage or unit rate per kWh. It is not the total divided by kWh, which includes standing charges.
Does standby power actually matter?
Collectively yes. A 5 W standby draw runs to 43.8 kWh a year, and a household with a dozen such devices loses several hundred kilowatt-hours.
Why does my heater cost more than this says?
Because thermostats cycle and resistive heating runs at full draw whenever it is on. Also check whether your tariff has a higher peak rate.
What uses the most in a typical home?
Heating and cooling, then hot water, then the fridge — which is modest per hour but never switches off.
Where these figures come from
- International Energy Agency — Energy Efficiency — appliance consumption and standby power context
- US Energy Information Administration — the federal energy statistics agency
Last checked: September 2026. Appliance power figures are typical ratings; check the label on your own equipment, which is authoritative for it.