Enter how many kilowatt-hours (kWh) you have used and your price per kWh in pence, and this works out the cost. The rate defaults to the current electricity price cap; for gas, change it to about 7.33p.
This is the calculation behind every line of your energy bill. If you have a wattage rather than a kWh figure, convert it first with the watts to kWh calculator. To see how the unit rate and the daily standing charge combine into a full bill, use the energy bill estimator, and for what the rate actually is, see how the energy price cap works.
Common questions
How do I work out the cost of 1 kWh?
Take your unit rate in pence and divide by 100 to get pounds. At the current cap of 26.11p, one kWh of electricity costs just over 26p. Gas is cheaper, around 7.33p per kWh.
What is a good price per kWh?
Under the July to September 2026 price cap, electricity averages 26.11p per kWh and gas 7.33p per kWh on a standard variable tariff. A fixed deal may be a little above or below this.