Appliance running cost calculator
What each appliance actually costs over a year. The results are usually not what people expect, because wattage matters far more than how often something is switched on.
How this is calculated
Cost is wattage divided by 1,000, multiplied by hours a day, days a year, and your unit rate. That gives kilowatt hours and then pounds.
Wattage dominates. A 3,000 watt kettle used for 20 minutes a day costs more than a 10 watt device left on permanently, which is why chasing standby power rarely saves much.
Anything that heats or cools is where the money goes: showers, dryers, ovens, kettles. Electronics are almost always a rounding error next to them.
Appliances with thermostats, like fridges and freezers, cycle on and off. Use the hours they actually run rather than the hours they are plugged in, which is why the fridge default is 8 rather than 24.
Rates used · 2026/27
| Formula | watts ÷ 1000 × hours × days × rate |
| Electric shower | 7,000 to 10,500 watts |
| Tumble dryer | 2,000 to 3,000 watts |
| Fridge freezer | 100 to 200 watts, cycling |
| Standby | usually pennies a year per device |
Last checked July 2026. Source: HMRC and gov.uk.
Worked example
An 8,500 watt electric shower run for 12 minutes a day uses 621 kWh a year and costs £152 at 24.5p. That is more than a fridge freezer running most of the day, and nearly twice a gaming PC used three hours daily. Across these six appliances the total is £652 a year.
Common questions
Where do I find the wattage?
On the rating plate, usually on the back or underside, or in the manual. It is given in watts or kilowatts, where 1 kW is 1,000 W.
Is standby power worth worrying about?
Rarely. Modern devices draw around half a watt on standby, which is pennies a year. The effort is better spent on the shower and the dryer.
Why is my fridge set to 8 hours rather than 24?
Because a thermostat cycles the compressor on and off. It is plugged in all the time but only drawing power for roughly a third of it.
Does this cover gas appliances?
No. This is electricity only. Gas is charged per kWh at a much lower rate and needs its own calculation.