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Disclaimer: The figures provided by this calculator are examples only and should be used for illustrative purposes. Actual costs will vary based on individual circumstances, driving habits, vehicle specifications, energy prices, and other factors. This calculator does not constitute financial advice.
This calculator provides realistic cost comparisons by accounting for real-world factors that affect EV and petrol/diesel running costs in the UK.
Miles per gallon (mpg) measures how many miles a vehicle travels on one UK gallon (4.546 litres). We convert this to miles per litre, then calculate annual fuel consumption and multiply by your fuel price.
Miles per kilowatt-hour (mi/kWh) measures EV efficiency. Typical family EVs achieve 3.5-4.5 mi/kWh. Small EVs can reach 4.5+ mi/kWh, while larger SUVs achieve 3.0-3.5 mi/kWh.
Electricity pricing: UK standard tariffs average £0.24/kWh. Dedicated EV tariffs offer off-peak rates of £0.07-0.10/kWh. Public rapid charging costs £0.50-0.85/kWh.
Petrol/diesel: We apply driving adjustments (urban -12%, mixed baseline, motorway +8%), convert mpg to litres, then calculate annual cost. Electric vehicles: We apply multiple adjustments—city driving improves efficiency by 10%, motorway reduces it by 20%, cold weather reduces by 15%, charging losses add 10%. We calculate your blended electricity cost based on home/public charging mix, then determine cost per mile.
Example: 80% home charging (£0.24/kWh) + 20% public (£0.65/kWh) = £0.322/kWh blended rate. At 3.6 mi/kWh effective efficiency, cost per mile is 8.9p.
Charging location has the biggest impact on costs. For 10,000 annual miles: home charging on standard tariff costs ~£600/year, public rapid charging costs £1,300-2,100/year, off-peak EV tariff costs just £175-250/year. Home charging with an EV tariff delivers 1.5-2.5p per mile—6-8x cheaper than petrol.
EVs are most efficient in city traffic due to regenerative braking, achieving 10-15% above rated efficiency. Motorway driving at 60-70mph reduces efficiency by 15-25% due to aerodynamic drag. A 4.0 mi/kWh rated EV might achieve 4.5 mi/kWh in the city but only 3.0-3.2 mi/kWh on motorways.
Batteries operate less efficiently below 10°C, and cabin heating consumes 2-3 kW continuously. Combined, winter conditions reduce efficiency by 10-20%, adding £100-200 to annual costs for average drivers. Minimise impact through preconditioning while plugged in and using heated seats instead of cabin heating.
AC-to-DC conversion is 85-92% efficient, losing 8-15% as heat. A 60 kWh battery requires 65-68 kWh from the wall. Our calculator's 10% loss adjustment ensures costs reflect actual consumption.
Diesel engines are 15-25% more efficient but cost 3-7p more per litre. Both remain 2-3x more expensive than home-charged EVs (4-6x vs off-peak EV tariffs).
Dedicated EV tariffs (Octopus Intelligent Go, EDF GoElectric, British Gas Electric Driver) offer off-peak rates of £0.07-0.10/kWh—65-70% cheaper than standard rates. Save £400-500/year for 12,000 annual miles.
Home charging is 2-3x cheaper than public rapid charging. Charge to 80-90% at home before journeys, use public charging only when necessary, and consider workplace charging if available.
Under-inflated tyres reduce efficiency by 3-5%. Check pressures monthly when tyres are cold, maintaining manufacturer-recommended levels.
Eco mode optimises power and climate control. Accelerate smoothly, anticipate traffic, maintain steady speeds, and use cruise control. Gentle driving improves efficiency by 10-15%.
Enable one-pedal driving if available. Anticipate stops early, allowing regenerative braking to recover energy. Proper use can recover 10-25% of energy used during acceleration.
Warm/cool cabin and battery before departure while connected to power. Uses grid electricity instead of battery, improving winter range by 5-10% on short trips.
Use heated seats and steering wheel (50-100W) instead of cabin heating (2-3kW). Set moderate temperatures, use recirculation mode, and consider layering clothing in winter.
Driving 60-65mph instead of 70mph improves efficiency by 15-20%. A 100-mile journey takes 14 minutes longer but saves 17-20% energy.
Climbing uses ~0.3 kWh per 100m elevation. Routes with 200m elevation gain use 10-15% more energy than flat alternatives. Choose flatter routes when possible.
Charge to 80% daily, 100% only for long trips. Avoid depleting below 10-20%. Minimise rapid charging. Park long-term at 50-60% charge. Maintains efficiency over 8-10 years.
We are proud to work in partnership with all NHS Trusts and several Health Care organisations to further support our NHS and Health Care professionals.
Find out more about these partnerships by clicking the logos below.
