Ask most UK drivers what their car costs and they will quote you the price on the forecourt or the monthly finance payment. Ask them what a single mile costs, and you will usually get a blank look. Yet cost per mile is the single most honest number in motoring. It rolls fuel, servicing, tyres, insurance, tax and depreciation into one figure that tells you exactly what you pay every time the wheels turn.
Whether you are a private driver trying to budget for the year ahead or a small fleet operator deciding how to price a job, getting your cost per mile right changes the decisions you make. This guide explains what belongs in the calculation, how the numbers look in 2026, and where the easy savings hide.
What "cost per mile" actually means
Cost per mile is simply your total motoring costs divided by the miles you drive. If you spend £6,000 a year running a car and cover 10,000 miles, your cost per mile is 60 pence. It sounds straightforward, but the figure is only useful if you are honest about what goes into the top of that sum.
The mistake almost everyone makes is treating cost per mile as "fuel cost per mile". Fuel is the most visible expense because you pay it at the pump, but for many drivers it is less than half of the true running cost. When you leave out depreciation, servicing and insurance, you dramatically understate what driving really costs — and you make poor decisions as a result, from overpaying for a thirsty car to underquoting a delivery job.
The two flavours: marginal vs. total cost per mile
There are two versions of the number and they answer different questions.
Marginal cost per mile is what one extra mile costs you *today* — mostly fuel or electricity, plus a small slice of tyre and servicing wear. This is the figure that matters when you are deciding whether to drive somewhere or take the train.
Total (or fully-loaded) cost per mile includes the fixed costs you pay whether you drive or not: insurance, road tax, depreciation, breakdown cover and finance interest. This is the figure that matters for budgeting, for business mileage claims, and for pricing work. A fleet operator who quotes on marginal cost alone will slowly go out of business.
The costs that make up every mile
To build an accurate figure, you need to gather every category of spend. Broadly, they fall into two buckets.
Running (variable) costs rise with the miles you cover:
- Fuel or electricity — the biggest variable cost for most drivers.
- Tyres — a set typically lasts 20,000 to 30,000 miles and a mid-range set costs £300–£500 fitted.
- Servicing and maintenance — oil, filters, brakes, wipers and the unglamorous repairs that keep an older car legal.
- MOT — capped at £54.85 for a car, but the repairs it uncovers are not.
Standing (fixed) costs you pay regardless of mileage:
- Depreciation — usually the single largest cost of ownership, and the one drivers most often ignore because no invoice ever arrives.
- Insurance — annual premiums that keep climbing.
- Vehicle Excise Duty (road tax) — set by the DVLA according to emissions and value.
- Finance interest or the opportunity cost of the cash tied up in the car.
- Breakdown cover and parking permits.
Add all of these for a year, divide by your annual mileage, and you have your total cost per mile. It is worth reading our fuller breakdown of car running costs in the UK to see how each category behaves as a car ages and mileage climbs.
Cost per mile in 2026: what the numbers look like
Every car is different, but ballpark figures help you sense-check your own maths. Based on typical 2026 UK prices, here is how the picture tends to look for a car covering around 10,000 miles a year.
Petrol and diesel
With petrol hovering around 140p a litre and a car returning 45 mpg, fuel alone works out at roughly 14p per mile. Diesel is a touch dearer at the pump but often more efficient on longer runs, so the fuel-only figure lands in a similar range for a mixed driver. Add servicing, tyres, an MOT and the odd repair, and running costs climb to perhaps 22–28p per mile before you touch the fixed costs.
Once depreciation, insurance and tax go in, a typical mid-size petrol or diesel car costs somewhere between 45p and 70p per mile all-in. Newer, pricier cars sit at the top of that range because they shed value fast; older paid-off cars sit lower because depreciation has already done its worst.
Electric
Electric vehicles flip the balance. Charge at home on an off-peak tariff and your "fuel" cost can drop to 4–7p per mile — a fraction of petrol. Rely on public rapid chargers, though, and the figure can rival or exceed petrol, so where you charge matters enormously. EVs also carry lower servicing costs but historically steeper depreciation, which can offset the fuel savings. If you are weighing the options, our fuel comparison of petrol, diesel, electric and hybrid breaks the trade-offs down in detail.
The headline: never judge cost per mile on fuel alone. An EV can look twice as cheap as petrol on marginal cost yet finish level once depreciation is counted.
How to calculate your own cost per mile
The only figure that truly matters is *your* figure, built from *your* receipts. Here is a reliable method.
- Choose a period. Twelve months is ideal because it captures the annual costs — insurance, tax, MOT and a service — that a single month would miss.
- Add up every cost. Pull together fuel receipts, servicing and repair invoices, tyres, insurance, road tax, breakdown cover and finance interest. Don't forget the small stuff; it adds up.
- Estimate depreciation. Note what the car was worth at the start of the year and what it is worth now. The difference is a real cost even though no money changed hands. A rough rule is 15–25% of the car's value in year one, tapering as it ages.
- Find your mileage. Take your odometer reading now and twelve months ago, or use MOT records to reconstruct it. Our guide to MOT mileage records explains how to pull historic readings if you don't have them to hand.
- Divide. Total costs ÷ total miles = cost per mile.
If that sounds like a lot of spreadsheet work, it is — which is exactly why we built a cost per mile calculator that does the arithmetic for you once you enter your numbers. It separates variable from fixed costs so you can see both your marginal and total figures at a glance.
Why fleets need to be especially precise
For a small business, cost per mile is not trivia — it is the foundation of pricing. If you run vans or pool cars, an error of a few pence per mile multiplied across tens of thousands of miles becomes thousands of pounds of unbudgeted cost or under-recovered revenue. Accurate per-vehicle tracking also feeds into HMRC mileage claims and helps you spot the vehicle that is quietly costing far more than the rest of the fleet. Keeping clean records with vehicle expense tracking turns a guessing game into a management decision.
How to bring your cost per mile down
Once you know your number, you can attack it. The biggest wins usually come from the costs drivers pay least attention to.
Tackle depreciation first. Because it is the largest cost for most owners, buying a two-to-three-year-old car and running it for longer slashes the per-mile figure. Someone else has already absorbed the steepest drop in value.
Drive for economy. Smooth acceleration, correct tyre pressures and less weight in the boot can improve real-world fuel economy by 10% or more. Removing an unused roof rack alone can save several percent at motorway speeds.
Shop around for fuel. Prices vary widely between forecourts, and the gap is often 10p or more a litre. Checking live UK fuel prices before you fill up is a five-second habit that compounds across a year.
Service on time, not late. A well-maintained engine burns less fuel and avoids the expensive failures that wreck a year's budget. Preventative maintenance is almost always cheaper than the repair it prevents.
Review insurance annually. Loyalty rarely pays. Comparing cover at renewal, adjusting your mileage estimate to reflect reality, and considering telematics can trim one of the larger fixed costs.
For a longer list of tactics, our guide on how to reduce car running costs goes into each of these in depth.
Frequently Asked Questions
Q: What is the average cost per mile to run a car in the UK?
A: For a typical petrol or diesel car covering around 10,000 miles a year, the fully-loaded cost — including depreciation, insurance and tax — usually lands between 45p and 70p per mile in 2026. Fuel-only cost is far lower, around 12–16p per mile, which is why quoting fuel alone badly understates the true figure.
Q: Does cost per mile include depreciation?
A: The total, or fully-loaded, cost per mile should include depreciation because it is a genuine cost of ownership — often the largest one. Many drivers ignore it because no bill ever arrives, but the fall in your car's value between one year and the next is real money. Leave it out and you will underestimate your true cost significantly.
Q: Is an electric car cheaper per mile than petrol?
A: On marginal cost it usually is, especially if you charge at home on an off-peak tariff, where electricity can cost 4–7p per mile against 12–16p for petrol. However, once you add depreciation and public rapid-charging costs, the total gap narrows and can even close. Where and how you charge is the deciding factor.
Q: How do I calculate cost per mile for my own car?
A: Add up every cost over twelve months — fuel, servicing, tyres, insurance, tax, MOT, breakdown cover and depreciation — then divide by the miles you covered in that period. Using MOT records for historic mileage and a dedicated calculator makes the process quick and far more accurate than guessing.
Q: Why does cost per mile matter for a small fleet?
A: It is the basis for pricing work and controlling costs. A few pence of error per mile, multiplied across a fleet's annual mileage, becomes thousands of pounds. Accurate per-vehicle tracking also supports HMRC mileage claims and highlights which vehicles are costing more than they should.
Conclusion: know your number, then shrink it
Cost per mile is the number that cuts through every other motoring figure. It tells a driver whether a journey is worth making and tells a business whether a job is worth taking. The drivers and fleets who thrive are the ones who track it honestly — fuel and depreciation, servicing and insurance, all of it — rather than fixating on the price at the pump.
The good news is you don't need a spreadsheet or an accountant to do it. CarFile brings your fuel, servicing, tax and mileage into one place, works out your real cost per mile automatically, and shows you exactly where the savings are. Start tracking your true cost per mile with CarFile today and turn a vague worry into a number you control.