Energy Bill Calculator Trending

Your energy bill is made up of two components, a daily standing charge and a unit rate for the energy you actually use. The standing charge covers the cost of maintaining your connection to the gas and electricity networks. The unit rate is the price per kilowatt-hour (kWh) of energy consumed. Ofgem's typical household uses 2,500 kWh of electricity and 9,500 kWh of gas a year (figures revised down from 2,700 and 11,500 in July 2026), and those two numbers together with the four rates are all the arithmetic requires.

The Ofgem energy price cap sets the maximum unit rates and standing charges that suppliers can charge on default tariffs, and it is reset quarterly in January, April, July and October. Around 50 to 60% of the level it allows reflects wholesale energy costs, with networks taking 20 to 25%, policy costs 10 to 15% and the supplier's margin 3 to 5%. From 1 October to 31 December 2026 the cap is 26.32p per kWh for electricity plus 54.83p a day, and 7.97p per kWh for gas plus 29.68p a day, for Direct Debit customers averaged across Great Britain. That puts a typical dual-fuel household at £1,723 a year. Electricity carries no VAT from 1 October 2026 to 31 March 2027, while gas still carries 5%, so the electricity figures are not directly comparable with earlier quarters. For scale, the Energy Price Guarantee held a typical bill to £2,500 through the winter of 2022-23.

Enter your actual meter readings or an estimate of consumption and you get the expected annual bill, split between unit costs and standing charges for each fuel, with the option to compare tariff rates and see what switching would save. Working from real readings rather than the typical household figures is worth the effort, because consumption varies far more between homes than prices vary between suppliers.

Whether to fix is the question most people arrive with. Fixed deals carry a premium of 5 to 15% above the current cap, so you gain if the cap then rises by 20% or more, and lose if it falls, as it has done several times across 2024 and 2025. Wholesale gas futures and Ofgem announcements are the only real guide. Fixing buys certainty when prices are stable or drifting down, whereas staying on the cap makes sense when prices are volatile but trending lower. Octopus, EDF, OVO, Eon and British Gas all offer fixed deals, and uSwitch or MoneySavingExpert will compare them.

Homes with a smart meter can go further with a time-of-use tariff. Octopus Agile tracks the wholesale market every half hour, ranging from 0 to 30p per kWh and occasionally going negative on sunny, windy days. Octopus Go, built around electric vehicles, charges 7 to 9p per kWh between 00:30 and 05:30 and around 30p at peak, saving EV drivers £600 to £1,200 a year against a flat rate. Octopus Cosy does the same job for heat pumps, cheap in the morning and evening and expensive at midday. Owners of solar panels on these tariffs sell their surplus back at 15 to 20p per kWh.

On the consumption side the order of effectiveness is fairly consistent. Switching tariff saves £100 to £300 a year. Turning the thermostat down by one degree saves £100 to £150, draught-proofing doors and windows £100 to £200, washing at 30°C around £50 and shorter showers £50 to £100, while closing the curtains at night costs nothing at all. Insulation comes next, worth £50 to £150 a year in the loft and £100 to £250 for cavity walls. Solar panels save £500 to £1,400 a year once they have paid for themselves, and a heat pump can be slightly more efficient than a gas boiler depending on the tariff and how well the house holds its heat.