Electricity Cost per kWh UK: Calculate Appliance Running Costs

What is the electricity cost per kWh in the UK?

There is no single electricity price for every UK household. Your cost per kWh depends on your tariff, region, payment method and whether you use a single-rate or multi-rate meter. The exact figure appears on your tariff information and electricity bill as a unit rate in pence per kWh.

For England, Scotland and Wales, Ofgem’s average capped electricity unit rate for a standard variable tariff paid by Direct Debit is 26.11p per kWh until 30 September 2026. It becomes 26.32p per kWh from 1 October to 31 December 2026. Regional rates vary, fixed tariffs can be different, and the Ofgem price cap does not apply in Northern Ireland.

The examples below use 26.32p per kWh so that the arithmetic matches the forthcoming October rate. Replace 26.32 with the unit rate shown on your own bill.

Electricity cost calculator formula

The basic appliance running-cost formula is: watts ÷ 1,000 × hours used × unit rate in pence per kWh = cost in pence.

For example, a 240-watt appliance used for one hour consumes 0.24 kWh. At 26.32p per kWh, the calculation is 240 ÷ 1,000 × 1 × 26.32, giving a cost of 6.32p.

If an appliance shows kilowatts rather than watts, leave out the division by 1,000. A 2kW heater used for one hour consumes 2 kWh and costs about 52.64p at the example rate.

• Find the appliance power rating in watts (W), usually on its label, plug or manual.
• Divide the wattage by 1,000 to convert watts to kilowatts (kW).
• Multiply by the number of hours used to calculate electricity consumption in kWh.
• Multiply the kWh by your unit rate to calculate the running cost.

Worked appliance running-cost examples

A 3,000W kettle running for three minutes uses 0.15 kWh: 3,000 ÷ 1,000 × 0.05 hours. At 26.32p per kWh, that is about 3.95p. A 10W LED bulb used for five hours consumes 0.05 kWh and costs about 1.32p.

For daily and annual costs, multiply the result by how often the appliance is used. A 100W appliance running for four hours every day uses 146 kWh a year: 0.1kW × 4 hours × 365 days. At the example rate, that costs about £38.43 a year before any standing charge.

These calculations are best for equipment that draws a fairly steady amount of power. Kettles switch off, heaters cycle with a thermostat, and washing machines use different amounts during each stage. For those appliances, a measured kWh-per-cycle figure, energy label or plug-in energy monitor will normally produce a better estimate than maximum wattage multiplied by the full running time.

How to calculate a whole electricity bill

An appliance calculation covers energy use only. A household electricity bill also includes a daily standing charge, which is payable even on a day when no electricity is used.

To estimate a bill, subtract the previous meter reading from the latest reading to find the number of kWh used. Multiply that usage by the unit rate, then add the daily standing charge multiplied by the number of days in the billing period.

Using the Ofgem averages from 1 October 2026, a household using 250 kWh over 30 days would have an energy charge of £65.80. Adding 30 days at the 54.83p average standing charge gives £16.45, producing an illustrative total of £82.25. Your actual rates may be higher or lower.

• Usage charge: kWh used × unit rate.
• Standing charge: number of days × daily standing charge.
• Estimated bill: usage charge + standing charge, plus or minus any tariff-specific adjustments.

Economy 7 and time-of-use electricity costs

Economy 7, electric-vehicle and other time-of-use tariffs have more than one unit rate. Calculate peak and off-peak electricity separately, then add the results together with the standing charge.

For example, multiply daytime kWh by the day rate and night-time kWh by the night rate. Do not use a national single-rate average if your meter records separate registers, because it can give a misleading result. Your bill should show each rate and the consumption assigned to it.

How to get the most accurate cost estimate

Start with your own tariff rather than an advertised national average. Check whether the rate on your bill includes VAT and whether a tariff change took place during the period you are calculating. If the rate changed, split the usage at a meter reading near the change date where possible.

For individual appliances, use the energy label’s kWh-per-cycle or annual kWh figure when one is provided. Energy Saving Trust advises multiplying the stated yearly kWh consumption by your electricity price to estimate annual running cost. A plug-in energy monitor can help with appliances whose demand changes while operating.