Energy Bill Calculator UK: gas and electricity at the price cap

Each fuel has two parts: a unit rate for every kWh you use, and a standing charge for every day, whether you use energy or not. Both come from the Ofgem price cap for your region and how you pay, or from the rates you enter.

For example, 2,500 kWh of electricity at 26.32p per kWh and 54.83p a day (Great Britain average, Direct Debit, 1 October 2026 to 31 December 2026) costs £858.13 a year. Add 9,500 kWh of gas at 7.97p per kWh and 29.68p a day, and the bill for both is £1,723.61.

• Cost of the energy you use = kWh a year × unit rate
• Standing charge = 365 days × standing charge a day
• Cost of each fuel = cost of the energy + standing charge
• Cost per year = electricity + gas; per month = ÷ 12; per day = ÷ 365

Ofgem sets the energy price cap every three months. It limits the unit rate and the standing charge a supplier can charge on a standard variable tariff. From 1 October 2026 to 31 December 2026 the Great Britain average for people who pay by Direct Debit is 26.32p per kWh for electricity and 7.97p per kWh for gas (Ofgem). There is no VAT on electricity from 1 October 2026 to 31 March 2027. Gas still has 5% VAT, and the rates above include it.

The cap is a limit on the rates, not on your bill. You pay for the energy you use, so a bigger home or more use means a bigger bill. A fixed deal is a different price and is not covered by the cap.

Ofgem publishes typical domestic consumption values, which it uses for its headline bill. From 1 July 2026 they are, for a year: electricity 1,600 kWh (low), 2,500 kWh (medium) and 3,800 kWh (high); gas 6,000 kWh, 9,500 kWh and 14,000 kWh (Ofgem). For a multi-rate meter such as Economy 7 the electricity figures are 1,900 kWh, 3,400 kWh and 6,100 kWh.

Your own use may be quite different. Your latest bill or supplier account shows the kWh you used over the year, and that is the best figure to enter.

The standing charge is a fixed daily amount you pay for being connected, whether or not you use any energy. On the Great Britain average it is 54.83p a day for electricity and 29.68p a day for gas (Direct Debit). Over a year that is £200.13 for electricity and £108.33 for gas, which is why a home that uses no gas can still pay a bill.

Ofgem prints one unit rate for multi-rate meters, so the calculator uses it for every kWh. On a real Economy 7 tariff the night rate is lower and the day rate higher, and Ofgem assumes 58% of the electricity is used at the day rate. If you know your own day and night rates, work out the average for your use and enter it under "My own rates".

If you are on a fixed deal or a tariff that is not the price cap, switch "Prices" to "My own rates" under More options and enter the unit rate and the daily standing charge from your bill. The calculator then uses your rates and the kWh you choose.

The price cap is different in each of the 14 regions of Great Britain, because the cost of delivering energy differs. It is also different for Direct Debit, standard credit (paying when the bill arrives) and prepayment meters. Choose the ones on your bill. Northern Ireland has no Ofgem price cap, so the figures here do not apply there.

The result is an estimate at the price cap. Your supplier’s bill is the final figure, and it depends on the meter readings, your tariff and the date the price cap changes. The price cap changes every three months, so a year of bills will not all be at the rates shown.