Cost per unit of distance of your car
Fuel is the part you notice and the smallest part of the bill. This adds the ones you do not: insurance, tax, servicing and, above all, depreciation.
Your figures
Result
- Combustible1.395 €35,4 %
- Seguro400 €10,1 %
- Impuestos e ITV150 €3,8 %
- [object Object]500 €12,7 %
- [object Object]1.500 €38,0 %
- Total per year
- $3,945
- Per month
- $329
- Fuel alone, per unit of distance
- $0.093
- Fuel as a share of the total
- 35.4%
- Fuel per year
- $1,395
- Fixed costs per year
- $2,550
Breakdown
| Item | Per year | Per unit |
|---|---|---|
| Combustible | $1,395 | $0.093 |
| Seguro | $400 | $0.027 |
| Impuestos e ITV | $150 | $0.010 |
| Maintenance and repairs | $500 | $0.033 |
| Depreciation | $1,500 | $0.100 |
| Total | $3,945 | $0.263 |
What we assume
- Depreciation is the loss of value per year, not what you paid. A rough guide is 10% to 15% of the current value annually.
- Fixed costs are spread over the distance you drive, so driving less makes each mile more expensive.
- Parking, tolls, fines and finance interest are not included unless you add them to another line.
How it is calculated
Everything is added up over a year and divided by the distance driven:
cost per unit = (fuel + insurance + tax + servicing + depreciation) / distance
The number nobody counts
Depreciation. It never appears on a receipt, so it feels free, and it is usually the largest single cost of owning a car. A vehicle loses value sitting on the drive; that loss is as real as the fuel, you just pay it all at once when you sell.
Why driving less costs more per mile
Insurance, tax and most of the depreciation happen whether you drive or not. Spread over 5,000 miles a year they are enormous per mile; over 20,000 they are modest. It is the reason a rarely-used second car is such poor value.
An example
15,000 a year at 6 l/100 km with 400 insurance, 100 tax, 600 servicing and 1,500 depreciation comes to about 0.31 per unit of distance. The fuel is only 0.10 of that: under a third.
Frequently asked questions
How do I estimate depreciation?
Look up what your model sold for a year ago and what it sells for now. As a rough guide, 10% to 15% of current value a year, faster on a newer car and slower on an old one.
Why is my cost per mile so much higher than the fuel?
Because fuel is typically a quarter to a third of the real cost. The rest is fixed costs and depreciation, which you pay regardless.
Does this work for an electric car?
Yes, if you put the electricity cost in the fuel line. Electric cars usually have lower running costs and steeper early depreciation, so the total often lands closer than people expect.
Keep calculating
All tools →- Real fuel economy calculatorFuel put in and distance covered. That is all it takes to know what your car really does, rather than what the trip computer claims.
- Compare the fuel cost of two carsTwo cars, two consumption figures, two fuel prices. What the difference actually adds up to over the years you will keep it.
- Electric car charging costWhat a charge costs and how far it takes you. Including the energy you pay for that never reaches the battery, which nobody mentions.
- What a trip costs in fuelDistance, consumption and fuel price. What the trip really costs, tolls included, and whether the train was cheaper after all.
Updated on 2026-08-26. Calculations run in your browser; nothing you type is sent to a server.