Breakdown of a gas bill

Methodology

To estimate the breakdown of an average gas bill, we:

1. Took the sum of each category of cost (e.g. wholesale, network etc) and the pre-tax supply margin reported by the suppliers for gas.
2. Divided the gas sum by the total number of customers and added VAT at 5%.

Please note that chart calculations are drawn from suppliers’ reported total costs and total customer numbers, irrespective of tariff type. The chart will therefore reflect a mixture of the costs to supply dual fuel and single fuel customers. As such, the bill breakdown is an approximation – values may differ, for example, if gas-only customers use more gas than those customers who are also supplied with electricity.

The data presented is based on the latest available Consolidated Segmental Statements (CSS). It may differ from the data in the suppliers externally published CSS. This is because we have made some adjustments to the way exceptional items are reported to improve comparability.

Figures relate to the suppliers’ financial years. Five of the companies (British Gas, EDF, E.ON, npower and ScottishPower) have financial years ending in December, whereas SSE’s financial year runs from April to March.