Ask most people what it costs to run their car and they'll quote you a fuel figure. Maybe they know their insurance premium off the top of their head too. But the full list of what car ownership actually costs, per mile, per year, across the life of the vehicle, is something most people have never sat down and totalled up. When they do, it's almost always a surprise.
The numbers that hide in plain sight
Fuel is the cost you pay attention to because it's frequent, variable, and you're standing at the pump watching the number go up. A tank of diesel at €90 is a real, present, uncomfortable expenditure. So fuel feels like the car's main cost.
It isn't. Not even close.
The biggest cost of owning a car is almost always depreciation, the difference between what you paid for it and what it's worth when you sell or scrap it. A car that costs €28,000 new and is worth €14,000 after five years has lost €14,000 in that time. That's €2,800 a year, or roughly €54 a week, for the privilege of owning it, and that cost runs every week whether the car moves or not. It doesn't appear on any bill and it's never itemised on a statement. It's just money that disappears quietly over time.
Finance charges are the other cost that often goes unnoticed in its full scale. A €20,000 car loan at 7% over five years costs you around €3,800 in interest on top of the principal. That's effectively a hidden price increase on the car that doesn't appear in any headline figure.
The full list of what it costs
Here is every cost that contributes to the real total of car ownership:
Depreciation. The gap between purchase price and resale value, spread across the years of ownership. New cars depreciate fastest, typically 20-30% in the first year. Cars two to four years old have survived the steepest part of the depreciation curve and represent better value per year of ownership.
Finance charges. If you borrowed to buy the car, the interest on that loan is a real cost of ownership. Even if you paid cash, there's an opportunity cost, the return you'd have earned if you'd invested that money instead. Both are real costs; the calculator handles the financed version explicitly.
Insurance. One of the most significant ongoing costs, and one that varies enormously by driver age, location, vehicle type and claims history. Irish insurance premiums average around €700-900 a year, but can be significantly higher for younger drivers or more powerful vehicles.
Road tax (motor tax in Ireland). A fixed annual cost based on engine size or CO2 emissions. Ranges from around €120 for low-emission vehicles to €2,350 for the highest-band vehicles.
Servicing and maintenance. The annual service, tyres, brake pads, wipers, the various items that wear out and need replacing. Budgeting €500-800 a year for a moderately new car is reasonable; older vehicles can cost significantly more.
Tyres. Often forgotten until they're needed. A full set of mid-range tyres costs €400-600. Depending on your mileage and driving style, you might replace them every four to six years. That's €80-150 a year that doesn't tend to appear in most people's car budget.
Fuel. The one people do track. Worth calculating honestly based on your actual mileage and consumption rather than the manufacturer's official figure, which is typically achieved under idealised conditions rather than real-world traffic.
Tolls and parking. These are real costs of using the car and belong in the total, particularly for commuters. Regular motorway tolls and daily parking can add up to several thousand euros a year for urban drivers.
What does all this add up to?
For a typical Irish driver covering around 15,000km a year in a mid-range car bought new for €30,000 and sold after five years:
Depreciation: €16,000 over five years = €3,200 a year.
Finance (if applicable): ~€1,500 a year on an average loan.
Insurance: €750 a year.
Motor tax: €280 a year (mid-range band).
Servicing and maintenance: €650 a year.
Fuel: ~€2,100 a year at typical consumption and current diesel prices.
Tyres and miscellaneous: €200 a year.
Total: approximately €8,680 a year. Over 15,000km, that's roughly €0.58 per kilometre, or about €0.93 per mile.
The fuel alone was €2,100, or €0.14 per kilometre. So fuel represents about 24% of the real cost per kilometre. The other 76% is invisible on a month-to-month basis, which is why so many people are surprised when they total it up.
Why this matters for specific decisions
The true cost per mile becomes relevant in a number of everyday decisions that most people navigate by instinct or rough estimate.
Commute by car or public transport? If your train pass costs €1,200 a year and your car costs €0.58 per kilometre and the commute is 30km each way, the car commute costs around €7,800 a year in real all-in terms (15,600km × €0.50, using slightly reduced annual costs since some are fixed regardless). The train wins by a significant margin, and that's before accounting for the stress, parking costs and the ability to read or work on the train.
Is it worth running a second car? The fixed costs of a second car, insurance, tax, depreciation, run whether you use it or not. If the second car sits mostly unused, it might be genuinely cheaper to use taxis or car sharing for the trips it would otherwise cover.
New versus used. A new car loses 20-30% of its value in the first year. A three-year-old car has survived that curve. The depreciation cost per year of ownership is typically much lower for a car bought second-hand, often less than half of what it would be for a new equivalent. The servicing cost might be slightly higher, but the total cost of ownership is usually lower.
Electric versus petrol or diesel. Electric vehicles have lower fuel costs (home charging is significantly cheaper than petrol per kilometre) and lower servicing costs (fewer moving parts, no oil changes, regenerative braking extends brake life). But the purchase price is higher, and depreciation on EVs is currently harder to predict. The calculator handles EVs the same way as any other vehicle, enter the purchase price, expected resale value, and fuel/charging cost, and it gives you the same all-in per-mile figure.
The mileage multiplier
One thing the per-mile cost reveals clearly: the more you drive, the more the fixed costs get diluted. If you put 30,000km a year on a car, the depreciation and insurance costs are spread across more kilometres, driving the cost per km down. If you drive 5,000km a year, those same fixed costs are spread across very few kilometres, making each one very expensive in real terms.
This is the core argument for considering whether a car is the right choice for low-mileage users. Someone who drives 5,000km a year in a car with €5,000 of fixed annual costs is paying €1 per kilometre in fixed costs alone, before fuel. Using taxis or car hire for those specific journeys might be significantly cheaper once honestly compared.
Put your own car's figures in and find out exactly what each mile of driving actually costs you.
Calculate your true cost per mile →Frequently asked questions
Should I use miles or kilometres?
The calculator supports both, there's a unit toggle at the top. Use whichever your country or driving habit uses. The underlying maths is identical; only the labelling changes.
How do I estimate the resale value?
Check a few listings for your make, model, and age on a site like Carzone or Done Deal in Ireland, or AutoTrader in the UK. The figures you find there for cars in good condition at the mileage you expect to reach are a realistic estimate. Be honest, private sale prices are higher than trade-in prices, and if you'll be trading in, use trade-in values.
Does depreciation apply if I plan to keep the car until it's worthless?
Yes, in the sense that a car reducing to €0 is the maximum possible depreciation, you've lost 100% of the purchase price over the ownership period. Keeping a car for a very long time doesn't reduce the depreciation cost; it amortises it more slowly. The per-year depreciation decreases, but the total doesn't.
What about the cost of breakdowns or major repairs?
These are genuinely hard to predict. Budget an average in the servicing field, a car with a history of expensive repairs might warrant €1,500 a year rather than €600. Alternatively, run the calculation at two different servicing costs and see how much it changes the per-mile figure.
Is the opportunity cost of paying cash included?
Not directly, but you can model it. If you paid €25,000 cash for a car, that money could otherwise have been invested. Use the "amount financed" field with the full purchase price and an interest rate equal to your expected investment return, this effectively models the opportunity cost of the cash you deployed.
How do I handle an electric car's charging costs?
Enter your average monthly charging cost in the fuel field. If you charge mostly at home, calculate your monthly electricity use for the car (kWh per month × cost per kWh) and use that figure. If you use public charging, include those costs too. The per-mile figure that comes out will reflect the real charging economics rather than a theoretical range figure.