Car Total Cost of Ownership Calculator

How it works

The cost of owning a car over a period is what you lose on the car itself plus everything you pay to run it. The loss on the car is its depreciation: the price minus what it is worth when you sell it. The resale value comes either from depreciation rates you can edit (a typical rule of thumb is about 20% in the first year, about 15% a year in years two and three and about 12% a year after that) or from a figure you enter, for example from a pricing guide.

Financing adds the interest paid while you own the car. For a loan, the calculator works out the level monthly payment and counts the interest in the payments made during your ownership: payments made minus the principal they repaid. If you sell before the loan is paid off, the remaining balance is principal, not a cost, and is not counted. You can instead enter the finance charge from your loan documents, or choose cash for no financing cost.

Yearly running costs (fuel or charging, insurance, maintenance and repairs, registration, and parking and tolls) are multiplied by the number of years. The total is then divided by the years, the months and the miles driven to give the cost per year, per month and per mile.

The running-cost defaults are AAA's Your Driving Costs 2026 weighted averages for top-selling 2026 models at 15,000 miles a year. In that study depreciation is the largest single cost ($4,422 a year on average), and the total comes to $12,863 a year, or $0.8575 a mile, at 15,000 miles.

Formula

depreciation = price − resale value
resale value (rates) = price × (1 − r₁) × (1 − r₂) × … × (1 − r_years)
loan payment = P × i ÷ (1 − (1 + i)^−n),   i = APR ÷ 12,   n = term in months
interest = payment × k − (P − balance after k),   k = min(n, 12 × years)
running costs = (fuel + insurance + maintenance + registration + parking) × years
total = depreciation + interest + running costs
per year = total ÷ years;  per month = total ÷ (12 × years);  per mile = total ÷ (miles per year × years)

Example

A $35,000 car kept 5 years at 15,000 miles a year, on the default depreciation curve, is worth $15,666.11 at the end: $19,333.89 of depreciation. $30,000 financed at 7% for 60 months costs $594.04 a month, or $5,642.16 of interest over the loan. AAA's 2026 average running costs ($2,598 fuel, $2,098 insurance, $1,759.50 maintenance and $802 registration) add $7,257.50 a year, $36,287.50 over five years.

The total is $61,263.55: $12,252.71 a year, $1,021.06 a month, or 81.68¢ a mile over 75,000 miles. Depreciation is 31.6% of it.

Assumptions and limitations

• Depreciation rates are a typical rule of thumb, not a forecast for any model; enter your own rates or a resale value from a pricing guide. Selling costs, trade-in negotiation and changes in the used-car market are not modelled.
• Running costs are the same every year, in today's dollars: no inflation, no rise in repair costs as the car ages, and no change in fuel prices. The defaults are AAA's 2026 national averages at 15,000 miles a year; they do not change when you change the miles, so edit them for your own driving, location and vehicle.
• Loan interest assumes level monthly payments made on time, with no prepayment. Principal financed above the purchase price (taxes, fees or negative equity rolled in) is not counted as a cost; add it to the price if it applies. Money paid up front is not charged a forgone return.
• Sales tax and fees at purchase are included only if you add them to the price. Tires, washing and accessories are counted only if you include them in the figures you enter.
• This is an estimate for comparison and budgeting, not financial advice.

Frequently asked questions