EV vs Petrol Running Cost Calculator

Compare the annual running costs of an electric car and a petrol car using your mileage, energy prices and vehicle efficiency.

Your Details

Your driving

miles

Your electric car

mi/kWh
%
p/kWh
p/kWh
£

Your petrol car

p/litre

Live petrol average unavailable. Enter your own price.

mpg
£

Annual Running Costs

Estimated fuel and energy running costs, plus servicing. Not the full cost of owning either car.

Enter your details and press calculate.

How the running costs are calculated

Each figure is a whole-year running cost, rounded to the nearest pound. The saving is the rounded petrol cost minus the rounded EV cost, so the three figures always add up.

  1. Electricity used
    Annual mileage ÷ EV efficiency (mi/kWh).

  2. EV Annual Cost
    Electricity used × (% at home × home price + remaining % × public price), pence to pounds, plus annual EV servicing.

  3. Petrol Annual Cost
    Annual mileage × (4.54609 litres ÷ MPG) × petrol price (p/litre), pence to pounds, plus annual petrol servicing.

  4. Annual saving with EV
    Petrol Annual Cost − EV Annual Cost. A negative result means petrol is cheaper to run.

  5. Cost per mile
    Each annual cost ÷ annual mileage × 100, in pence. Servicing is included.

Worked example

10,000 miles a year. Electric car: 4 mi/kWh, 80% charged at home at 7.5p/kWh, the rest at 65p/kWh, £150 servicing. Petrol car: 40 mpg, 140p a litre, £450 servicing.

EV Annual Cost
£625
Petrol Annual Cost
£2,041
Annual saving with EV
£1,416

EV: 10,000 ÷ 4 = 2,500 kWh. Blended price 80% × 7.5p + 20% × 65p = 19p. 2,500 × 19p = £475, plus £150 servicing = £625. Petrol: 10,000 × (4.54609 ÷ 40) = 1,136.52 litres × £1.40 = £1,591.13, plus £450 servicing = £2,041.13, rounded to £2,041. Saving £2,041 − £625 = £1,416.

Assumptions and limits

  • The calculator estimates fuel, energy and servicing running costs only. Purchase price and depreciation are not included, so it is not the full cost of owning either car.
  • The home-charging percentage must be between 0 and 100. The rest of your charging is priced at the public rate.
  • Petrol use is converted from miles per gallon using the UK (imperial) gallon of 4.54609 litres.
  • Charging losses, insurance, tax and finance are not included.
  • The grey numbers in the fields are hints, not values. Enter your own figures, including a petrol price you have checked.

Key Takeaways

  • In the worked example, the EV costs about 6.3p per mile to run and the petrol car about 20.4p per mile, servicing included.
  • Public charging costs can significantly affect the comparison. Depending on electricity prices, petrol prices, efficiency and mileage, either vehicle could have lower running costs.
  • The bigger the gap between your public and home electricity prices, the more a larger public-charging share narrows the saving.

Sources

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