"Is an EV cheaper to run than petrol?" has a real answer, and it is not the flat yes or the flat no you usually hear. The honest reply is that it depends on one thing above all others: where and how you charge.
Get that right and an electric car is dramatically cheaper to fuel. Get it wrong and the headline saving mostly disappears. Everything else, servicing, tax, insurance and depreciation, then nudges the total up or down from there.
The one thing that decides it
Before any of the detail, settle a single question: can you charge at home, overnight, on a cheap electricity tariff? That answer moves the running-cost gap more than every other factor combined.
Why home charging changes everything
A dedicated overnight EV tariff prices electricity far below the standard rate for a few hours in the small hours. Charge then and you are buying miles at a fraction of the pump price. The car sits on the driveway filling up while you sleep, and you never queue.
If you cannot charge at home
No driveway means leaning on public chargers, which cost far more per unit. That is the case where the maths can flip, and petrol sometimes stays cheaper overall. So work out your likely charging pattern first, then read the rest of this with that in mind.
Energy vs fuel: the pence-per-mile maths
The fair way to compare a car you plug in with one you fill up is cost per mile, not the price of a "tank". The maths is simple once you have the two numbers.
How to work out petrol pence per mile
Take the pump price per litre, convert to price per gallon (multiply by about 4.55), then divide by the car's real miles per gallon. A typical petrol car returning 40 to 50 mpg lands somewhere around the mid-teens of pence per mile at recent pump prices. Thirsty cars and town driving push it higher.
How to work out EV pence per mile
Take the price you pay per kilowatt-hour, then divide by the car's real efficiency in miles per kWh (most sit around 3 to 4). Charge at home on a cheap overnight rate and the result is often low single-digit pence per mile, a large saving on petrol. Charge at the standard domestic rate and it climbs, but usually still beats petrol. The Energy Saving Trust keeps up-to-date figures if you want current numbers rather than the shape of the sum.
Prices move constantly, so treat any fixed figure as out of date the week you read it. What does not change is the method: pence per unit divided by miles per unit, both sides the same way.
Public charging: where the savings disappear
Home charging is the cheap end. Public charging is a different price bracket entirely, and it is the single biggest reason the "EVs are always cheaper" claim falls apart for some drivers.
Rapid and ultra-rapid cost far more
Motorway and forecourt rapid chargers can cost several times the cheap overnight home rate per unit. At those prices an EV's pence per mile can rise to sit level with petrol, and on the dearest ultra-rapids it can be worse. The convenience is real, but so is the cost.
Who this hits hardest
Drivers with no home charging who do most of their charging on public rapids lose the headline advantage. Do the sum on public prices before assuming an EV will save you money. If most of your charging would be cheap and at home with the occasional rapid on a long trip, the average stays low. If it is the other way round, the average creeps up towards petrol.
Servicing, tyres and maintenance
Fuel is the loud number. Maintenance is the quiet one, and here the EV has a structural advantage that does not depend on how you charge.
Fewer parts to go wrong
An electric motor has a fraction of the moving parts of a petrol engine. There is no engine oil, no cambelt, no clutch, no exhaust or gearbox in the usual sense. That removes a long list of routine service items and the bills that come with them, so scheduled servicing is usually cheaper.
Where EVs cost more, and less
It is not all one way. EVs are heavy and deliver instant torque, so tyres wear faster and are a real running cost, not a footnote. Brakes, by contrast, tend to last longer because regenerative braking does much of the slowing, so pads and discs get an easy life. Net, maintenance still tends to favour the EV, but budget for tyres.
Tax and insurance
Two costs have moved against EVs in recent years, and both need to be in the total rather than waved away with old "free to tax, cheap to insure" lines.
EVs now pay road tax
From April 2025 electric cars pay Vehicle Excise Duty like petrol and diesel, ending the era of free road tax. Worse for pricier models, an EV over the list-price threshold also pays the expensive-car supplement for several years, which adds a meaningful annual sum. The current rates and thresholds are set out on gov.uk, and they are worth checking against the exact car before you assume EV tax is cheap.
Insurance often costs more
EVs frequently sit in higher insurance groups. Repair costs can be steeper, specialist parts and labour are dearer, and the battery is an expensive component to risk in a shunt. Get real quotes on the specific car rather than trusting a rule of thumb, because the spread between models is wide.
Upfront cost and depreciation
Running costs are only part of the picture. What you pay to own the car, and what you lose when you sell it, often matters more to the total than fuel ever will.
The higher price to buy
Like for like, EVs still tend to cost more to buy than the equivalent petrol car. That upfront gap has to be earned back through cheaper running, which takes time and depends on your mileage and charging.
Depreciation can dwarf the fuel saving
Some EVs have depreciated steeply as the used market and technology moved fast, and a heavy loss in value can wipe out years of fuel savings on its own. This is why total cost of ownership, the whole cost across the years you keep it, is the number that matters, not pence per mile alone. For a plain-English walk through the running costs of any car, MoneyHelper is a good neutral starting point.
So who actually wins
There is no universal answer, but the pattern is clear once you know two things: how you charge and how far you drive.
A rough guide, not a verdict on a specific car. Charging prices, tariffs and tax rates move, so run your own numbers before you decide.
The clearest case for an EV
A driveway, a cheap overnight tariff, and plenty of miles a year. Cheap home electricity times high mileage is a big number, and it pays back the higher purchase price fastest.
The clearest case for petrol
No home charging, low annual mileage, and a reliance on public rapids. The fuel saving is small because you drive little, and it is eroded further by dear public units, so petrol can still be cheaper across the whole of ownership.
Check the exact car before you commit
Averages decide the type of car. The individual car decides the risk, and that is where cheap running costs can be undone by a bad buy. A free MOT history check shows how a used EV or petrol car has held up, our mileage check flags an odometer that does not add up, and the reliability pages show how a model fares as it ages. If you drive in a city, the ULEZ checker confirms whether the exact car pays a clean-air charge, which is a running cost in its own right.
Common questions
How fast does an EV battery lose range?
Slowly. Real-world data on modern packs points to roughly 1 to 2% capacity lost a year for a typical car, so most keep the great majority of their range well past 100,000 miles. Manufacturers back this with a separate battery warranty, usually eight years or 100,000 miles, guaranteeing the pack stays above about 70% health in that window. A failing pack is the expensive worry, so the warranty matters more than the odometer.
Can I run an EV without a driveway?
Yes, but the sums change. On-street residents can use lamp-post and bollard chargers, workplace points, or destination chargers at supermarkets and gyms. These sit between home and rapid prices, so the per-mile cost lands in the middle rather than at the cheap home rate. If none of those are within reach and you would rely on rapids, petrol often stays cheaper overall.
Is there still help to fit a home charger?
For some. The old universal grant closed, but a targeted EV chargepoint grant still helps renters and people in flats with off-street parking cover part of the cost of a home point. The rules and amounts are set out on gov.uk, and eligibility is the thing to check before you assume you must pay the full install price.
Do electric cars pay the ULEZ or clean-air charge?
No. Fully electric cars meet the emissions standard in London's ULEZ and other UK clean-air zones, so they pay nothing to drive in them, which is a real saving for city drivers. That exemption is separate from road tax, which EVs do now pay. You can confirm any specific car against the zones with our ULEZ checker.