Depreciation is usually the biggest line item
For most cars, the drop in value dwarfs any single running cost — often more than insurance, fuel and maintenance combined. Comparing a purchase against leasing instead? See the Auto Lease Calculator, or check Car Affordability before you shop.
Frequently asked questions
What counts as depreciation here?
Purchase price minus the resale value you expect to get back when you sell or trade it in. If you don't know the resale value, a rough rule of thumb is 15-20% of the price lost per year, faster in year one.
Should I include loan interest?
This tool covers ownership costs, not financing. If you're borrowing to buy, add the total interest from the Car Loan Calculator to get the full picture.
Why does cost per mile matter?
It lets you compare cars of very different prices and running costs on equal footing, and is the same metric used for mileage reimbursement and ride-share cost math.
Last updated: June 2026