EV vs petrol running-cost comparison
Compare the running cost of covering the same distance by EV versus petrol, using your own efficiency and price figures.
Result
EV cost
Petrol cost
EV saving vs petrol
How to use this calculator
- Enter the distance you want to compare.
- Enter your (or a typical) EV efficiency and electricity price.
- Enter your (or a typical) petrol car's mpg and fuel price.
- Read both costs and the difference.
Assumptions
- Uses whichever electricity price you enter — home overnight charging and public rapid charging can differ by several times, so the result is highly sensitive to this figure.
- Does not include either vehicle's purchase price, depreciation, insurance, servicing or road tax — fuel/energy running cost only.
Technical details: what the fields mean
- Distance
distanceMiles - The distance to compare running costs over — use your annual mileage for a yearly comparison.
- EV efficiency
evEfficiencyMiPerKwh - EV miles travelled per kWh.
- Electricity price
evPricePerKwh - Electricity price per kWh.
- Petrol fuel economy
petrolMpg - Petrol car's miles per UK gallon.
- Petrol price
petrolPricePerLitre - Petrol price per litre.
Methodology
EV cost = (distance ÷ efficiency) × price per kWh. Petrol cost = (distance ÷ mpg) × 4.54609 × price per litre. Saving = petrol cost − EV cost.
Worked example
10,000 miles/year, EV at 3.5mi/kWh & 30p/kWh vs petrol at 45mpg & £1.45/L
Inputs: distanceMiles=10000, evEfficiencyMiPerKwh=3.5, evPricePerKwh=0.3, petrolMpg=45, petrolPricePerLitre=1.45
Result: EV £857.14, petrol £1,464.85, saving £607.71
Practical guidance
- Run this with your actual home electricity tariff for the most realistic comparison — the result changes a lot between a cheap overnight EV tariff and a standard rate.
- This compares fuel/energy cost only — total cost of ownership also depends on purchase price, depreciation and servicing, which vary by specific vehicle.
Common mistakes
- Using a public rapid-charging price when most of your charging is actually done cheaply at home overnight.
- Treating this as a full cost-of-ownership comparison rather than a running-cost-only comparison.
FAQs
Is an EV cheaper to run than a petrol car?
Usually yes on a per-mile energy-cost basis when charged at home, but the gap depends heavily on your electricity tariff and driving pattern — use your own figures above.
Does this include the cost of buying the car?
No — this compares fuel/energy running cost only, not purchase price, depreciation, insurance or servicing.