What goes into the cost per mile
A car costs far more than the fuel you put in it. To find what it really costs to drive one mile, add up everything the car costs you in a year and divide by the miles you drive in that year. This cost per mile calculator splits the costs into two groups, because they behave very differently.
- Fixed costs come due whether you drive or not: insurance, registration and other yearly fees, depreciation, loan interest and parking.
- Driving costs, also called variable costs, grow with every mile: fuel, maintenance and repairs, and tires.
Depreciation is easy to overlook, because you never write a check for it. You pay it when you sell the car for less than you paid. The calculator spreads the purchase price minus the expected resale value evenly over the years you keep the car.
In kilometers the fuel cost per km is liters per 100 km ÷ 100 × the price per liter. With UK mpg, the calculator turns miles per imperial gallon into liters at 4.54609 liters per gallon and takes the fuel price per liter.
A worked example
The example car in the calculator cost $30,000 and should sell for $15,000 after 5 years, so it loses $3,000 a year. It does 28 mpg on fuel at $3.50 a gallon and is driven 12,000 miles a year. These are example values, not averages, so put in your own.
| Cost | Per year | Per mile |
|---|---|---|
| Insurance | $1,800 | 15¢ |
| Registration and fees | $300 | 2.5¢ |
| Depreciation | $3,000 | 25¢ |
| Loan interest | $700 | 5.8¢ |
| Parking | $600 | 5¢ |
| Fuel | $1,500 | 12.5¢ |
| Maintenance and repairs | $900 | 7.5¢ |
| Tires | $192 | 1.6¢ |
| Total | $8,992 | 74.9¢ |
Fixed costs make up $6,400 of the $8,992, which is 53.3 cents a mile. The driving costs add 21.6 cents a mile. That split matters for the next question.
Why driving more lowers the cost per mile
Fixed costs are spread over the miles you drive, so the same car looks cheaper per mile the more you use it, even though the yearly bill goes up. Here is the example car at different yearly mileages, with everything else the same:
| Miles per year | Cost per year | Cost per mile |
|---|---|---|
| 5,000 | $8,005 | 160.1¢ |
| 8,000 | $8,428 | 105.4¢ |
| 12,000 | $8,992 | 74.9¢ |
| 15,000 | $9,415 | 62.8¢ |
| 20,000 | $10,120 | 50.6¢ |
| 25,000 | $10,825 | 43.3¢ |
Depreciation is kept the same in this table. If you expect extra miles to lower the price you can sell the car for, lower the resale value in the calculator as well.
The cost of one extra trip
When you decide whether to drive somewhere or take another option, the full cost per mile overstates what the trip costs you. Insurance, registration and the loan cost the same either way. What changes is the fuel, tire wear and maintenance, so the calculator prices one extra trip with the driving costs only. With the example car, a 20-mile trip costs about $4.32. Enter your own trip length in the One extra trip field. Parking at the destination or tolls come on top.
The full cost per mile is the right number for the bigger questions: whether you need a second car, whether a cheaper car would pay off, or what to charge when someone else uses your car.
Your cost per mile next to the IRS rate
The IRS publishes standard mileage rates that taxpayers can use to work out the deductible cost of driving for business, instead of adding up actual expenses. For 2026 the business rate was 72.5 cents a mile from January 1 to June 30, according to the IRS announcement of the 2026 rates. In Announcement 2026-11 the IRS raised it to 76 cents a mile for driving on or after July 1, 2026, citing increases in the price of fuel. That is about 47.2 cents a km. The rate for charitable driving is fixed by law at 14 cents a mile.
The IRS says the business rate is based on an annual study of the fixed and variable costs of operating a car, and that using the standard rate is optional: you may deduct actual costs instead, under the rules the IRS sets. The IRS table of standard mileage rates lists the rates for every year. The calculator shows the comparison when the currency is US dollars. If your cost per mile is above the rate, the table under the result shows which costs drive it. With few miles a year, the fixed costs weigh the most. This page is not tax advice; check the IRS rules or ask a tax professional before you claim anything.
Where to find your own numbers
- Insurance and registration: your policy and your renewal notice. Add up the yearly totals.
- Resale value: look at asking prices for the same model with the age and mileage your car will have when you sell it.
- Loan interest: your loan statement shows the interest paid this year. The car loan calculator shows the total interest, which you can divide by the years of the loan.
- Fuel economy: your own fill-ups give the most honest figure. The MPG calculator works it out from your odometer and receipts.
- Maintenance: add up last year's receipts for service and repairs, or the schedule in your owner's manual.
How to use the cost per mile calculator
- 1Pick miles with US or UK mpg, or kilometers, and enter how far you drive in a year.
- 2Fill in the fixed costs: insurance, registration, what you paid for the car, what you expect to sell it for and when, loan interest and parking.
- 3Enter your fuel economy, the fuel price, maintenance and what a set of tires costs and how long it lasts.
- 4Read the cost per mile, the split into fixed and driving costs, the yearly and monthly totals and the cost of one extra trip, then copy the result or a link.
For the fuel cost of one road trip, use the trip fuel cost calculator.
Frequently asked questions
How do I calculate my car’s cost per mile?
Add up everything the car costs you in a year, then divide by the miles you drive in that year. Fixed costs are insurance, registration, depreciation, loan interest and parking. Driving costs are fuel, maintenance and tires. The example car in the calculator costs $8,992 a year over 12,000 miles, which is 74.9 cents a mile.
What is the IRS mileage rate for 2026?
For business use it is 72.5 cents a mile for January 1 to June 30, 2026, and 76 cents a mile from July 1, 2026, after the IRS raised it mid-year because of higher fuel prices. The rate for charitable driving stays at 14 cents a mile. Check irs.gov for the rate that applies to the date of your trip.
What is the difference between fixed and driving costs?
Fixed costs come due whether you drive or not: insurance, registration, loan interest, parking and depreciation as this calculator counts it. Driving costs, also called variable costs, grow with every mile: fuel, tires, and maintenance and repairs. Drive more miles and the fixed costs are spread thinner, so the cost per mile falls.
Should depreciation be part of the cost per mile?
Yes, if you want the real cost. The car loses value every year you own it, and that money is gone when you sell it, even though you never write a check for it. The calculator spreads the purchase price minus the expected resale value over the years you keep the car.
What does one extra trip really cost?
Only the driving costs, because insurance, registration and the loan cost the same whether you make the trip or not. With the example car, a 20-mile trip costs about $4.32 in fuel, wear and maintenance, far less than 20 times the full cost per mile.
Can I use kilometers and liters?
Yes. Choose Kilometers to enter the distance in km, fuel economy in liters per 100 km and the fuel price per liter. The result is then a cost per km. Switching units converts the numbers you already typed.