A year of driving, line by line

Ask someone what their car costs per month and you will get a number that is roughly the gas. It is a completely reasonable answer, because gas is the only part that involves standing somewhere watching a total go up. Everything else arrives annually, or once, or never as a payment at all.

So here is the whole thing, worked out with federal figures rather than estimates. The example is an eighteen-thousand-dollar used car kept eight years and sold for six thousand.

Where each number comes from

• Miles per year: 11,026, the average for a light-duty short-wheelbase vehicle.^[1]
• Fuel consumption: 24.7 miles per gallon for the same class, which is 4.05 gallons per hundred miles.^[1]
• Gasoline: 3.49 dollars a gallon, the mean of the 52 weeks to 17 August 2026. The range across that year was 2.78 to 4.50.^[2]
• Insurance: 1,281 dollars, the countrywide average expenditure per insured vehicle.^[3]
• Maintenance, tires and registration: from household spending divided by the 1.8 vehicles an average household owns.^[4]

The part that is not on any statement

Gas and depreciation are almost exactly the same size here, and only one of them arrives as a payment. On this car the gas costs $1,558 a year; the depreciation is 12,000 dollars spread over eight years, so 1,500. One of them you watch tick upward on a screen forty times a year. The other you meet once, on the day you sell, and by then it reads as bad luck rather than as the cost it was.

Which of the two is bigger is not a fact about cars, it is a fact about your car. Depreciation is a share of the purchase price; gas is a share of the miles. At the mileage and pump price used here, the two cross at a purchase price of about 18,700 dollars if you sell for a third of what you paid. Below that, gas wins and the honest answer really is roughly the gas. Above it, depreciation pulls away fast – a 35,000-dollar car sold for 12,000 after eight years loses 2,875 dollars a year, nearly twice the gas bill. That is the whole reason the calculator asks for the purchase price instead of assuming one.

That is why the gas answer is so persistent. It is not ignorance. It is that gas is the only part of car ownership with a receipt.

What to do with this

Not necessarily sell the car. For a great many people in the United States a car is not a lifestyle choice, it is the condition of having a job, and an article that concludes otherwise is written for somewhere with trains. The useful outcome is smaller and more durable: you now know the real per-mile number, which means the next decision, a second car, a longer commute for more pay, a more expensive replacement, can be made with the whole figure instead of the gas.

Not sure what to enter for yearly miles? Estimate your annual mileage from dated odometer readings and a plan of the trips you actually make.

Frequently asked

Sources

1. Highway Statistics 2023, Table VM-1: 11,026 miles per light-duty short-wheelbase vehicle and year, 24.7 miles per gallon, Federal Highway Administration, retrieved August 22, 2026.
2. Weekly U.S. Regular All Formulations Retail Gasoline Prices: 3.49 dollars per gallon as the mean of the 52 weekly readings from 25 August 2025 to 17 August 2026 (range 2.779 to 4.500), U.S. Energy Information Administration, retrieved August 22, 2026.
3. Auto Insurance Database Report: countrywide average expenditure of 1,281.60 dollars per insured vehicle in 2023, National Association of Insurance Commissioners, retrieved August 22, 2026.
4. Consumer Expenditure Survey 2024, per consumer unit: 984 dollars maintenance and repairs, 217 dollars tires, 148 dollars vehicle registration, 63 dollars vehicle property tax, 1.8 vehicles owned, U.S. Bureau of Labor Statistics, retrieved August 22, 2026.

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