Energy Cost Calculator

Every appliance you plug in has a power rating in watts, and every unit of electricity you buy has a price in pence per kilowatt hour (kWh). Put the two together and you can work out exactly what anything costs to run - from a single LED bulb to an electric shower.

Pick one of the preset appliances below or type in a wattage (you'll usually find it on a label on the appliance itself), set the unit rate from your bill, and the calculator does the rest.

How appliance running costs are worked out

The calculation behind this tool is the same one your electricity meter does all day: divide the appliance's wattage by 1,000 to get kilowatts, then multiply by your unit rate.

A 3,000W kettle is 3kW. At a unit rate of 26p per kWh, running it costs 3 x 26p = 78p per hour. A kettle only takes a few minutes to boil, so a single boil works out at roughly 3p - it's the appliances that run for hours, like heaters and tumble dryers, that really move your bill.

What common appliances cost to run

Based on a unit rate of 26p per kWh (roughly the current price-cap level - use your own rate in the calculator for accurate figures):

Costs assume the appliance draws its full rated power for the whole hour.

Power rating vs real-world use

An appliance's wattage is its maximum draw, not what it uses every second it's switched on. Thermostat-controlled appliances - fridges, ovens, heaters, washing machines - cycle their heating elements on and off, so a "150W" fridge freezer might average closer to 40W across a day. The calculator's figures are a ceiling; a smart meter or a plug-in energy monitor will show you the real number for your exact appliance.

How to cut appliance running costs

• Target the big loads first: heating, hot water and anything that dries or heats (tumble dryers, dishwashers, electric showers) dominate most bills.

• Run washing machines and dishwashers full, on eco settings, at lower temperatures.

• Check for appliances that run 24/7 - an old second fridge or freezer can cost more per year than it would cost to replace.

• Make sure you're not overpaying per kWh in the first place - the unit rate multiplies every single appliance in this list, so switching to a cheaper tariff cuts every row at once.

Frequently asked questions

Which appliances use the most electricity?

Anything that heats or cools: electric showers, immersion heaters, tumble dryers, ovens and portable heaters top the list for power draw. Fridges and freezers use far less power but run around the clock, which is why they still show up near the top of annual consumption tables.

How do I find an appliance's wattage?

Look for the rating plate - a sticker or engraving on the back or base of the appliance - which lists the power in watts (W) or kilowatts (kW). It's also in the manual and on the manufacturer's website. If you only have amps (A), multiply by 230 to get an approximate wattage.

Is electricity cheaper at night?

Only on time-of-use tariffs such as Economy 7 or EV tariffs, which offer cheaper overnight rates in exchange for pricier daytime ones. On a standard single-rate tariff the price is the same around the clock.

Why is my bill higher than the calculator suggests?

Your bill also includes the standing charge - a fixed daily fee you pay regardless of usage - plus every other appliance in the building. This calculator prices one appliance at a time, so it's best used for comparing and spotting the expensive ones.