Petrol vs Electric Car Cost Calculator

What should I know about True Cost of Car Ownership?

Purchase price and fuel are only part of the story. Full cost includes: fuel, Vehicle Excise Duty (VED/road tax), insurance, servicing and maintenance, MOT and repairs, depreciation (the largest single cost for most cars), and parking/charging infrastructure. Depreciation alone accounts for 40–60% of total ownership cost for most cars in the first 3 years. A £30,000 car that is worth £18,000 after 3 years has depreciated £12,000 — more than many years' fuel costs combined.

What should I know about Electric Car Economics?

Electric cars have high purchase prices but very low running costs: fuel at home charging (7p/kWh off-peak) costs 2–3p per mile vs 15–20p for petrol. Servicing is simpler (no oil changes, fewer brake replacements due to regenerative braking). VED is £0 for zero-emission vehicles. The break-even point depends heavily on the price premium over equivalent petrol, annual mileage, and whether you can charge at home. For high-mileage drivers with home charging, EVs are clearly cheaper. For low-mileage drivers, or those without home charging access relying on public rapid chargers, the running-cost advantage narrows considerably and the payback period on the higher purchase price can stretch well beyond typical ownership length — run the numbers on your actual annual mileage and charging setup rather than assuming EVs are automatically cheaper.

What should I know about Depreciation by Fuel Type?

Depreciation rates vary significantly by fuel type and model. Petrol: mainstream models typically retain 40–50% of value after 3 years. Diesel: similar to petrol but uncertainty around future diesel restrictions has increased depreciation in urban areas. Electric: higher initial depreciation (40–50% in first 3 years) due to technology improvement reducing second-hand values, though this is improving. Hybrid: strong residuals (50–60% retained) due to high demand for fuel-efficient used cars. Always factor depreciation into a true cost-per-mile comparison alongside fuel and maintenance, since it's typically the single largest cost of car ownership over 3-5 years — a cheap-to-run car that loses value fast can end up costing more overall than a pricier one that holds its value.

What do I need to know about BIK and Company Cars?

For company car drivers, Benefit in Kind (BIK) tax is a significant consideration. Electric vehicles have very low BIK rates (2% of list price in 2026/27, rising 1% per year to 2027/28) — making them dramatically cheaper than petrol equivalents for higher-rate taxpayers. A £40,000 EV at 2% BIK vs an equivalent petrol at 32% BIK: the BIK difference alone is worth £2,800–4,800/year in tax for a 40% taxpayer. For company car users, the shift to EVs is financially compelling regardless of personal usage patterns or driving style, since the tax saving is baked into the BIK banding rather than dependent on mileage — this is the single strongest financial argument for choosing an EV as a company car, and the gap only widens as petrol BIK rates continue to rise in scheduled annual increments while EV rates stay low.

What's the key thing to understand about Fuel Cost Comparison Depends on Charging Access?

The running-cost comparison between a petrol and an electric car depends heavily on where and how the electric car is charged, more so than almost any other single factor. A driver with off-street parking and the ability to install a home charger, particularly one who can access a cheap overnight electricity tariff designed for EV charging, typically sees the largest cost advantage from switching to electric, since home charging on a low off-peak rate is usually considerably cheaper per mile than petrol. A driver without home charging access who relies mainly on public charging — especially public rapid or ultra-rapid chargers, which carry a premium price for speed and convenience — may see a much smaller cost advantage, and in some cases find public charging costs approach or even exceed petrol costs per mile, since public charging infrastructure operators price for convenience and speed rather than matching the economics of cheap home electricity. This single factor — realistic access to affordable home charging — is often more important to the financial case for switching to electric than the specific models being compared, which is why the same comparison can produce very different conclusions for two otherwise similar drivers depending purely on their parking and charging circumstances, and is worth honestly assessing before assuming an EV will automatically be cheaper to run.

What should I know about Government Incentives and Total Cost of Ownership?

Beyond the direct fuel-versus-electricity cost comparison, several other financial factors commonly favour electric vehicles in many markets, though the details vary significantly by country and change periodically with policy. Vehicle tax (road tax or equivalent) has historically been lower or zero for electric vehicles in many jurisdictions compared with petrol cars, though several governments have begun phasing out these advantages as EV adoption grows, so current rules should always be checked rather than assumed to continue indefinitely. Company car tax in some markets has offered particularly significant savings for electric vehicles compared with petrol equivalents, making EVs especially attractive for employees with a company car benefit. Servicing and maintenance costs are generally lower for electric vehicles due to fewer moving parts and reduced brake wear from regenerative braking, as outlined in dedicated EV-versus-petrol running cost comparisons. On the other side of the ledger, electric vehicles have often carried a higher upfront purchase price than a directly comparable petrol equivalent, though this gap has been narrowing over time as battery costs fall and more competitively priced EV models reach the market, and resale value and depreciation patterns for EVs have been less predictable historically than for petrol cars with a longer established used-car market track record — a genuinely complete total cost of ownership comparison needs to weigh all of these factors together over a realistic ownership period, not fuel cost in isolation.

Worked Example: 12,000 Miles a Year, Petrol vs Electric Running Costs

Comparing a typical mid-size petrol car against a comparable electric car over 12,000 miles a year (roughly the UK average) isolates just the energy cost side of the comparison, before purchase price, depreciation, or incentives are factored in.

The spread in the electric row is the whole story: an electric car charged mostly at home overnight on a cheap off-peak tariff can cost roughly a tenth of the equivalent petrol car to run, while the same electric car relying mostly on public rapid chargers can end up costing as much as or more than petrol once the much higher per-kWh price of rapid charging is factored in. This is why driveway or off-street parking with home charging access is such a decisive factor in whether an EV actually saves money day to day — the vehicle technology is identical, but the economics flip almost entirely based on where the electricity comes from.

Servicing, Tyres and the Maintenance Side of the Comparison

Fuel or energy cost is usually the headline comparison, but maintenance costs are a meaningful and often underestimated part of total running cost, and they consistently favour electric vehicles, though not universally or without caveats. Electric vehicles have far fewer moving parts in the drivetrain — no exhaust system, no multi-speed gearbox in most designs, no spark plugs, no engine oil to change, and regenerative braking that significantly reduces brake pad and disc wear compared with a petrol car's friction braking. Routine servicing bills for EVs have tended to run lower than for equivalent petrol cars over the first several years of ownership, reflecting this reduced mechanical complexity. Tyres are the counterpoint: EVs are typically heavier than an equivalent petrol car (due to battery weight) and deliver instant, strong torque, both of which tend to wear tyres faster, and many EVs require tyres with specific load ratings designed for that extra weight, which often cost more to replace than standard equivalents. Insurance has also historically run somewhat higher for some EV models, reflecting higher repair costs for battery and sensor-heavy components after an accident, though this varies significantly by model and has been narrowing as EVs become more common and repair networks mature. Taken together, lower routine servicing costs are usually enough to offset higher tyre and insurance costs for most owners, but the gap is narrower on the maintenance side than on the fuel side, and anyone budgeting precisely should get real insurance quotes for their specific model rather than assuming the general EV cost advantage automatically extends to every cost category.