Most running cost comparisons are built on a hidden assumption: that you charge your electric car at home, overnight, on a cheap tariff. Change that one variable and the whole calculation flips. Diesel can be cheaper per mile than a rapid-charged EV. This isn't a niche edge case - nearly half of UK households live in terraced houses or flats without access to a home charger. So before we get into the numbers, the honest question is: which situation describes you?

Key Takeaways

  • Electric (home charging) - cheapest to run at around 7p per mile; saves £600-£1,500 on fuel alone vs petrol annually
  • Electric (public rapid charging) - can cost 24p+ per mile, more expensive than petrol or diesel
  • Diesel - still the lowest cost-per-mile for high-mileage drivers who can't charge at home; 12.5-14.5p per mile
  • Petrol - most expensive fuel-cost option at 19-21p per mile, but maintenance and insurance often lower than diesel
  • Company car drivers - electric is the overwhelming winner due to 3% BiK rate vs up to 37% for petrol and diesel

The Numbers, Side by Side

Here is a straightforward cost-per-mile comparison based on current UK fuel and electricity prices:

Fuel type Cost per mile Annual cost (10,000 miles) Annual maintenance
Electric - home charging 7p £630 £165
Electric - EV off-peak tariff 7.5p £680 £165
Electric - public rapid charger 24p+ £2,400+ £165
Petrol 19-21p £1,230-£1,450 £205
Diesel 12.5-14.5p £1,250-£1,450 £205

The table tells two completely different stories depending on where you charge. Home-charging EV owners are paying less than a third of what petrol drivers pay per mile. Public-rapid-charging EV owners are paying more than everyone else.

Why Home Charging Changes Everything

Home charging is what makes electric cars economically viable for most private buyers. Charging overnight on a dedicated EV tariff, or even a standard off-peak rate, brings the cost down to 7-7.5p per mile. That compares favourably with even the cheapest diesel.

The Electric Car Scheme's 2026 analysis models a like-for-like comparison between a VW ID.3 and a VW Golf over three years:

  • VW ID.3 (electric) total 3-year cost: £25,480
  • VW Golf (petrol) total 3-year cost: £32,385
  • Saving: £6,905

That saving comes from combining lower fuel costs, cheaper servicing, and tax advantages. It assumes home charging. Without it, the maths look very different.

The Public Charging Problem

Rapid public charging currently costs around 24p per mile - more expensive than petrol at today's fuel prices. A round trip from London to Penzance using rapid chargers in an EV costs around £148. The same trip in a diesel car costs around £77.

This is the number that goes viral on TikTok and Reddit, and it is real. The frustration from EV sceptics is legitimate: if you rely entirely on public charging because you live in a flat or terraced house, the claimed savings evaporate.

The UK government's own data acknowledges that almost half of households cannot easily charge at home. For these drivers, the economic case for switching to electric is genuinely weaker than the headline figures suggest.

Diesel: Not Dead Yet

Diesel remains the lowest cost-per-mile fuel option for drivers who cover high annual mileage and rely on public charging or no charging at all. At 12.5-14.5p per mile, diesel is cheaper per mile than petrol and significantly cheaper than public-rapid-charged electric.

Reddit's r/UKPersonalFinance threads on this topic consistently surface the same nuance: diesel makes sense for drivers covering 15,000-plus miles per year who do mostly motorway driving and have no home charging option. The fuel cost saving over petrol alone can exceed £500 per year at that mileage.

The caveat is that diesel is declining. New diesel cars are harder to find, residual values are falling, and cities are expanding clean air zones. Diesel is economically rational today for a specific type of driver - but it is a shrinking window.

Petrol: The Middle Ground Nobody's Excited About

Petrol is the most expensive option on a pure fuel-cost basis, but it comes with advantages that rarely appear in comparison tables. Petrol cars tend to be cheaper to buy than equivalent EVs or diesels. They are widely available in used markets. Insurance premiums are often lower than for EVs, partly because repair costs for internal combustion engines are more predictable.

For drivers doing low-to-moderate mileage - say, under 8,000 miles per year - the lower purchase price of a petrol car can offset the higher per-mile fuel cost when spread across total ownership. The CarSupermarket running cost comparison found the VW Golf petrol costs around £1,450 per year in fuel at 10,000 miles, while the equivalent ID.3 costs £750 - a saving of £700 per year. But if the EV costs £5,000 more to buy, you need seven years to break even on fuel alone.

Maintenance and Servicing Costs

Electric cars have fewer moving parts, no oil to change, no timing belts, and regenerative braking extends brake pad life significantly. The result:

  • EV annual servicing: approximately £165
  • Petrol/diesel annual servicing: approximately £205

The saving is real but modest - around £40 per year. It is not the headline advantage of electric ownership; fuel cost is. But over five or ten years it compounds into a meaningful difference, especially as petrol and diesel cars accumulate higher-cost repairs.

Tax and BiK: Where EVs Win Outright

For company car drivers, electric is the clear winner regardless of charging situation. The Benefit in Kind (BiK) tax rate for electric vehicles is 3% for 2025/26, compared to up to 37% for high-emission petrol and diesel cars.

A higher-rate taxpayer driving a £40,000 petrol car as a company vehicle could pay £5,000+ annually in BiK tax. The same person in an equivalent electric car pays around £480. The difference is larger than most drivers' annual fuel bills.

Road tax (Vehicle Excise Duty) is now levied on EVs as of April 2025, but electric cars pay the lowest rate. Standard petrol and diesel cars pay £195-£600 per year depending on emissions. EVs pay £195.

How to Calculate Your Own Break-Even

The right answer depends on your specific situation. Work through these four questions:

  1. Can you charge at home? If yes, electric almost certainly wins on running costs.
  2. What is your annual mileage? Under 8,000 miles, petrol may offer better whole-life value. Over 15,000, diesel or home-charging EV wins on fuel cost.
  3. Is this a company car? If yes, electric wins on BiK tax regardless of mileage.
  4. What is the purchase price difference? Divide the EV premium by the annual fuel saving to get your break-even year.

Interactive tools like the Zapmap journey cost calculator and Admiral's car cost calculator let you input your own mileage and charging patterns for a personalised figure.

Frequently Asked Questions

Q: Is it cheaper to run an electric car than a petrol car in 2026? It depends on how you charge. Home charging costs around 7p per mile vs 19-21p for petrol, making electric clearly cheaper. If you rely on public rapid chargers (24p+ per mile), petrol is currently cheaper. Around half of UK households cannot easily charge at home, which affects whether the savings materialise.

Q: Is diesel still worth buying in 2026? For high-mileage drivers without home charging, diesel remains the cheapest fuel per mile at 12.5-14.5p. However, diesel cars have lower resale values, face ULEZ and clean air zone restrictions in cities, and the new car market is shrinking. It is economically rational for a specific driver profile but a diminishing option.

Q: How much does it cost to charge an electric car at home vs a public charger? Home charging on an EV tariff costs around 7-7.5p per mile. Public rapid charging typically costs 24p or more per mile - around three times more expensive. A London to Penzance round trip costs £148 using rapid chargers vs around £77 by diesel.

Q: What is the cheapest fuel type for a company car driver? Electric, by a large margin. The 3% BiK rate for EVs in 2025/26 compares with up to 37% for high-emission petrol and diesel. A higher-rate taxpayer in a £40,000 petrol company car could pay over £5,000 in BiK tax annually; the equivalent EV costs around £480.

Q: How long does it take for an electric car to pay back its higher purchase price vs petrol? At 10,000 miles per year with home charging, fuel savings alone are around £700-£800 per year vs a petrol equivalent. If the EV costs £5,000 more to buy, the break-even point is roughly 6-7 years on fuel alone. Add in lower servicing costs and BiK savings and the break-even point shortens substantially.

Q: Does diesel or petrol have lower maintenance costs? Both are similar. Petrol and diesel cars cost around £205 per year to service versus £165 for electric vehicles. Electric cars have fewer components that wear out - no oil changes, no timing belts, reduced brake wear from regenerative braking. The saving is modest annually but compounds over long ownership.

The Honest Verdict

Electric wins on running costs - but only if you can charge at home. That qualifier matters enormously and gets glossed over in most comparisons. If you have a driveway and a home charger, the financial case for electric is clear and strengthens every year as fuel prices fluctuate.

If you live in a flat or a terrace with no off-street parking, the maths are more honest with diesel for high mileage or petrol for lower mileage - until public charging infrastructure improves and prices fall. That transition is happening, but it is not complete.

The debate on TikTok and Reddit is not really about which fuel is cheapest. It is about whether the UK's charging infrastructure is good enough to make the EV savings accessible to the half of the population who cannot plug in at home. On that question, the honest answer is: not yet.