Electric car versus petrol or diesel costs

Set annual kilometres, EV consumption, electricity price, fuel consumption and price per litre. Use comparable routes and driving patterns for both vehicles. For the EV, a consumption figure measured from the grid includes the charging energy you actually pay for.

Formula

Annual EV cost = annual km ÷ 100 × kWh/100 km × electricity price. Annual fuel cost = annual km ÷ 100 × litres/100 km × price per litre. Saving = fuel cost − EV cost; percentage saving uses fuel cost as its baseline.

Worked example

Over 15,000 km, an EV using 18 kWh/100 km requires 2,700 kWh. A combustion vehicle using 6 litres/100 km requires 900 litres. Applying the respective unit prices gives a like-for-like annual energy comparison.

What the result means

A positive saving means lower energy spending with the electric vehicle under these assumptions. A negative result means the entered charging arrangement costs more than the fuel scenario.

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

This is an energy-cost comparison, not a total ownership forecast. Depreciation, purchase price, taxes, insurance, maintenance and infrastructure costs can change the overall decision.

Questions answered

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