The headline reason people consider an electric car is running cost, and on the day-to-day numbers an EV genuinely tends to win, especially if you can charge at home. But fuel is only one line of the comparison. An honest look has to take in servicing, the caveats around public charging, and the bigger costs of owning the car at all. This guide works the per-mile maths through at current UK prices and is straight about where the EV advantage shrinks.
The short answer. Charged at home on a standard tariff at 26.11p per kWh, a typical EV doing about 3.5 to 4 miles per kWh costs roughly 7p a mile. On a cheap overnight EV tariff that can fall to around 2p a mile. A petrol car at 45mpg and petrol around 140p a litre costs about 14p a mile. So home charging usually halves or better undercuts petrol on fuel, and the EV also costs less to service. The caveats are a higher purchase price and the fact that relying on public rapid charging can push the per-mile cost up to petrol levels.
Energy versus fuel, per mile
This is where the EV pulls ahead, and the size of the lead depends almost entirely on where you charge. The maths is simple: cost per mile equals price per unit divided by how far the car goes on that unit.
An efficient EV does around 3.5 to 4 miles per kWh of electricity. A petrol car at 45mpg does 45 miles per 4.55 litres (a gallon). Put current prices through both and the gap is plain.
| Car and fuel source | Price | Efficiency | Cost per mile |
|---|---|---|---|
| EV, cheap overnight tariff | ~7p/kWh | 3.7 miles/kWh | ~1.9p |
| EV, standard tariff | 26.11p/kWh | 3.7 miles/kWh | ~7.1p |
| EV, public rapid charger | ~75p/kWh | 3.7 miles/kWh | ~20.3p |
| Petrol, 45mpg | ~140p/litre | 45 mpg | ~14.1p |
At 26.11p/kWh standard electricity, Ofgem cap July to September 2026. Overnight EV tariff and public charger prices vary widely; petrol price illustrative. Worked examples; check your own rates.
Even on a standard tariff the EV beats petrol per mile. On an off-peak EV tariff it is not close. That overnight rate is the lever that turns a modest saving into a large one, which is why when you charge matters as much as whether you go electric. The home charging cost guide has the full breakdown.
Servicing and maintenance
An electric car has far fewer moving parts than a petrol one. No oil to change, no spark plugs, no exhaust system, no clutch or gearbox of the usual kind, no cambelt, and far less to wear out generally. Regenerative braking, where the motor slows the car and recovers energy, even spares the brake pads, so they often last much longer than on a petrol car.
That generally means lower routine servicing and maintenance over the years. A petrol car carries a long, familiar list of consumables and services, oil and filters, plugs, belts, clutch, exhaust, that quietly add up across its life, and the EV sidesteps most of it. Tyres, wiper blades, brake fluid, cabin filters and the 12V battery still need attention, and EVs can be a little harder on tyres because they are heavier and have instant torque, but the overall maintenance bill is usually lower.
One more line in the running-cost column: an EV pays no fuel duty, and electricity used at home carries only 5 percent VAT against the heavy tax loaded onto petrol at the pump. That is part of why the per-mile energy gap is so wide, and it is a saving you bank on every mile rather than at a service interval. The trade-off is that road tax and insurance for EVs are not always cheaper, so check those for the specific car rather than assuming.
How long the expensive part, the traction battery, lasts is the question people worry about most. In practice modern batteries degrade slowly and are warrantied for years, covered in how long do EV batteries last.
The caveats, stated plainly
The day-to-day savings come with conditions, and it is more honest to put them up front than to bury them.
- No home charging changes the sum. If you cannot charge at home and rely on public rapid chargers, the per-mile energy cost rises sharply, as the table above shows, and can approach or exceed petrol. The main advantage depends on charging cheaply, usually overnight at home. If you have no driveway, the charging without a driveway guide covers the workarounds and their cost.
- Higher purchase price. Electric cars still tend to cost more to buy than an equivalent petrol model, though the gap is narrowing and the used market is changing fast.
- Depreciation. EV resale values have been less predictable than petrol, so depreciation is a real part of the lifetime sum, not just the energy.
- Winter range. Cold weather cuts range and pushes up the cost per mile a little, as EV charging in winter explains.
None of these wipe out the running-cost win for a home charger, but they mean the per-mile figure alone does not settle whether an EV is the better deal for you.
Putting it over a year
The per-mile gap looks small until you multiply it by a year's driving. For an average 7,000 miles a year, here is roughly what the fuel alone comes to.
| Car and charging | Cost per mile | Fuel cost for 7,000 miles |
|---|---|---|
| EV, cheap overnight tariff | 1.9p | ~£133 |
| EV, standard tariff | 7.1p | ~£497 |
| Petrol, 45mpg | 14.1p | ~£987 |
| EV, public rapid only | 20.3p | ~£1,421 |
Fuel and energy only; excludes purchase, insurance, depreciation and standing charges. Worked examples; check your own rates.
An EV charged overnight at home saves around £850 a year in fuel against a 45mpg petrol car over 7,000 miles. Charged on a standard tariff the saving is closer to £490. Rely on public rapid charging and the EV can cost more than petrol. The pattern is the same as everywhere else on this site: the saving is real, but it is the cheap overnight unit that does the heavy lifting. The EV cost versus petrol per year page expands this across different mileages.
If you still run petrol
Not everyone is ready to switch, and there is no need to feel pushed. If you keep a petrol car, the running cost is mostly in your driving style. Smooth, anticipatory driving, sensible speeds, correct tyre pressures and not carrying dead weight all trim the fuel bill, the habits gathered in the hypermiling guide. For an electric car the equivalent skill is charging at the right time, but the principle is the same: the car is only as cheap as the way you run it.
There is also a halfway option. A plug-in hybrid can run cheap electric miles around town and fall back on petrol for longer trips, but only if you actually plug it in. Left unplugged it carries a heavy battery around on petrol and is dearer than a normal hybrid. The plug-in hybrid running cost guide weighs that up honestly.
The whole picture
On running costs, the electric car generally wins: cheaper energy per mile, especially on an off-peak home tariff, and lower servicing thanks to far fewer moving parts. The fuel saving is the clearest single advantage of going electric, and over a year of home charging it is several hundred pounds.
The caveats are the upfront price, depreciation, and the fact that relying on public rapid charging undercuts the fuel saving. So decide on the whole-life cost and your charging reality, not the per-mile figure in isolation, but know that the per-mile figure is firmly in the EV's favour when you can charge at home. If you are comparing where to plug in, the home versus public charging cost and home charger versus a 3-pin plug guides cover the kit, and the broader driving and fuel hub ties the rest together.