Electricity cost calculator

Enter the power shown on the appliance label or measured at the socket. Choose watts or kilowatts, then set operating hours and days of use. The reference electricity price is an editable illustration; use the unit rate from your own bill for a more relevant estimate.

Formula

Energy in kWh = power in kW × hours of operation. A weekly schedule is multiplied by 365 ÷ 7; a monthly schedule uses days × 12, capped at 365. Cost = energy × price per kWh.

Worked example

A 1,000 W heater used for two hours every day consumes 2 kWh on each operating day and 730 kWh per year. Multiply 730 by your unit rate to estimate its annual energy cost.

What the result means

Daily results are averages across the whole year. Monthly results divide annual consumption by 12, so they represent an average month rather than a particular calendar month.

Electricity price · United Kingdom

£0.2611/kWh is Ofgem’s average capped electricity unit rate for standard variable tariffs paid by Direct Debit in England, Scotland and Wales, valid from 1 July to 30 September 2026. It includes 5% VAT and excludes the separate standing charge. It is not an average across all contracts and does not apply to Northern Ireland. Use your own tariff where available.

Last reviewed: 9 September 2026 · Ofgem · July–September 2026

Enter the unit rate including any applicable tax. Check your bill rather than adding a tax percentage automatically. Standing charges, export payments and subscription fees are separate. Ofgem information applies to Great Britain; Northern Ireland has its own regulator and market arrangements.

Assumptions and limits

Constant power and a repeated schedule are assumed. Thermostats, standby, seasonal use, standing charges and time-dependent tariffs can change the actual bill.

Questions answered

Methodology · Report an error