How the cost is worked out
Running cost is power multiplied by time, priced at your unit rate. A 2,000-watt heater on for one hour uses 2 kWh. At 26.32p per kWh that is about 53p; at 34.15p it is about 68p.
Appliances with a thermostat, such as ovens, fridges and heaters, switch on and off as they work, so they use less than their full rated power. The defaults above allow for this where it matters.
Where the biggest savings usually are
- Anything that heats water or air. Electric showers, immersion heaters, tumble dryers and plug-in heaters use the most power, so a few minutes less each day adds up fastest.
- Air fryer versus oven. For small portions, an air fryer usually costs less because it heats a much smaller space for a shorter time.
- Boil only what you need. A kettle draws a lot of power, so filling it for one cup rather than four cuts the cost of each boil.
- Fewer, fuller loads. Washing machines and dishwashers cost roughly the same per cycle whether full or half empty.
In Northern Ireland? Compare suppliers on the NI electricity cost calculator, or see whether oil beats electric heating on the heating oil calculator.
Common questions
How do I find out how many watts my appliance uses?
Look for a rating plate on the back or base of the appliance, or check the manual. It is usually shown in watts (W) or kilowatts (kW). 1 kW is 1,000 W.
Where do I find my electricity price per kWh?
Your bill or supplier app shows your unit rate, usually in pence or cents per kWh. Enter that figure for the most accurate result.
Is there VAT on electricity in the UK?
From 1 October 2026 to 31 March 2027, domestic electricity in England, Scotland and Wales carries 0% VAT. Northern Ireland keeps the 5% rate because EU VAT rules still apply there under the Windsor Framework.
Is it cheaper to run appliances at night?
Only if you are on a time-of-use tariff, such as Economy 7, with a cheaper night rate. On a standard single-rate tariff the price is the same at any time of day.
Why is my real bill different from this estimate?
Your bill depends on your exact tariff, any standing charge, how long each appliance really runs and how efficient it is. Use your own wattage and price for the closest estimate.