Per mile, with per kilometre alongside
This page reports in miles because that is what odometers, fuel economy and reimbursement policies use in the United States. The per-kilometre equivalent is shown on the same line for anyone converting a figure for use elsewhere; one mile is 1.609344 kilometres exactly, so a per-mile cost divided by 1.609344 gives the per-kilometre cost. The URL still says kilometres because it always has and links to it should keep working.
Fuel is the smaller half
Ask what it costs to drive somewhere and almost everyone answers with price divided by MPG. At $3.50 a gallon and 30 MPG that is 11.7 cents a mile, and it is a genuine number — it is simply not the cost of driving. Oil at $60 every 7,500 miles adds 0.8 cents. A $700 set of tires over 45,000 miles adds 1.6. Insurance, registration and general upkeep at $2,250 a year spread over 12,000 miles adds 18.8 cents by themselves, which is more than the fuel. The total lands near 33 cents a mile, and none of that includes what the car is losing in resale value while it sits.
The two figures serve different purposes and it is worth keeping them apart. When an employer reimburses mileage, or when you are settling up on a tank of gas, the fuel-only line is what people mean. When you are deciding whether to make the trip at all, or whether to keep the car, the full figure is the honest one.
Annual mileage moves the answer more than anything else
Every fixed cost in this calculation is divided by the miles you drive, so that field does more work than the rest combined. Insurance, registration and vehicle taxes come due on a calendar, not an odometer. A car driven 25,000 miles a year spreads them thinly; the same car driven 5,000 miles a year carries four or five times as much fixed cost on every mile.
The conclusion people draw from this is backwards more often than not. Low mileage does not mean a cheap car — it means an expensive one per mile, because the costs arrive regardless. If your annual mileage is genuinely low, the question worth asking is not how to drive more efficiently but whether the vehicle earns its place at all against renting, ride-hailing and car sharing for the trips you actually take.
Electric vehicles change the shape of the breakdown
Set the energy source to electricity, enter your rate in cents per kWh and your efficiency in miles per kWh, and set the oil interval to zero — there is no engine oil. The energy line usually drops sharply if you charge at home, and rises considerably if you rely on public fast charging. Maintenance falls, because oil, spark plugs, belts, exhaust components and much of the brake wear either disappear or stretch out. Tires tend to go the other way, since the vehicles are heavier and deliver torque immediately, so a shorter replacement interval in that field is realistic rather than pessimistic.
What that trade actually totals over years of ownership, including the purchase price gap and resale, is a separate question and lives on the EV versus gas total cost calculator.
What to do with the number
- Splitting a trip. Fuel plus tolls divided by heads is the usual convention and nobody argues with it. On a long drive, adding the wear line is fairer to whoever owns the car, since the trip genuinely consumed tires and an oil change.
- Mileage reimbursement. Most policies define a rate rather than asking for arithmetic, and where they leave it open, the fuel-only figure is the conservative claim. The gap between that and the full cost is what an owner absorbs.
- Drive or take a ticket. Enter the fare per person and the page finds the headcount where the car wins. It cannot price parking at the destination, and it cannot price the difference between four hours of driving and four hours of doing something else.
- Keep or sell. Divide the annual total by twelve and compare it to a month of the alternatives you would actually use. Add depreciation before you do, or the comparison flatters the car.
None of this is a prediction. It is a division problem applied to figures you supplied, and if the maintenance line turns out low or the tires wear faster than the interval you entered, the answer moves with them. Re-run it once a year with what actually happened and it will be worth more than any published average.
Questions people ask
Why is depreciation left out?
Because it does not divide sensibly by miles. A car left in a driveway for a year loses a substantial fraction of what the same car loses driving 15,000 miles, since age, model year, generation changes and market conditions drive resale value more than the odometer does. Spreading it across miles therefore misstates it in both directions: it looks trivial for a high-mileage driver and catastrophic for a low-mileage one, and neither impression is right. Treat it as an annual amount instead. Estimate what the vehicle is worth now and what it will be worth when you sell, divide by the years between, and add that to the annual total on this page. It will usually be the largest line in the whole calculation.
What should go in the insurance and registration fields?
Your own numbers off your own paperwork, and nothing else. Insurance premiums vary by state, ZIP code, vehicle, coverage limits, deductible, credit-based rating where it is permitted, and driving record, and the spread between two drivers of the same car in the same city is routinely a factor of two or three. Registration is at least as inconsistent: some states charge a flat fee that barely changes, some scale it by vehicle value or weight, some levy an annual personal property tax on vehicles at the county level, some add an inspection or emissions charge, and several now add a surcharge specifically for electric vehicles to offset lost fuel tax. There is no national figure worth quoting for any of it. Add up twelve months of what you actually paid.
How do I estimate maintenance if the car is new and nothing has broken yet?
Expect the early years to understate the later ones and plan for the curve rather than the current bill. A vehicle under warranty with fresh consumables genuinely costs very little beyond oil and filters, and that is not the steady state. Brake pads and rotors, a battery, wiper blades, cabin and engine air filters, an alignment, coolant and transmission service, suspension bushings and eventually more expensive items all arrive on their own schedule. A workable approach is to look at the maintenance schedule in the owner's manual, price the services listed for the next four or five years, add a contingency for the things that are not on any schedule, and divide by the years. Then revise the field each year using what you actually spent.
The trip comparison says driving is cheaper. Should I drive?
Not necessarily, because the comparison is deliberately narrow. It prices energy, wear and tolls against a fare, and it stops there. It does not price parking at the destination, which in a city centre can exceed the entire cost of the drive. It does not price the hours: a train passenger can work, read or sleep, and a driver cannot. It does not price fatigue on the return leg, which is a safety question rather than a financial one. It does not price the risk of the trip, or the extra depreciation those miles add to the vehicle. Use the figure as one input among several, not as the decision.