What goes into cost per mile
Your cost per mile has two halves. Variable costs scale with every mile you drive: fuel first, then maintenance, repairs, and tires — which AAA averages at roughly 9.6 cents per mile for a newer vehicle. Fixed costs arrive whether the car moves or not: insurance, registration, parking, and (for newer cars) depreciation. Spread over your annual mileage, fixed costs often surprise people — at low mileage they can dwarf fuel.
That is why cost per mile is so sensitive to how much you drive. A $1,000 insurance premium adds 20 cents per mile if you drive 5,000 miles a year, but under 7 cents at 15,000 miles. The calculator above keeps the two halves separate so you can see exactly where your money goes, and it accepts fuel economy as either MPG or L/100km.
What the number is good for
A realistic cost per mile turns fuzzy decisions into arithmetic: whether a 60-mile round-trip commute is worth it, what to charge a friend for sharing a drive, whether the train is actually cheaper, or what a side gig that pays per delivery really nets you. If you use a personal car for business mileage, comparing your true cost against your local per-mile reimbursement rate tells you whether that rate makes you whole.
It also reframes maintenance: at AAA's average, skipping a year of upkeep "saves" about $1,450 on paper — and quietly converts itself into repairs, faster wear, and a weaker resale story. Cost per mile makes those trade-offs visible.
From estimate to measurement
Every number in the calculator above is a guess you typed in. The same numbers exist as facts in your fuel receipts and service invoices — they just need to be written down. Odobook logs fill-ups (and computes your actual MPG or L/100km from them), services, and repairs per vehicle, then shows real cost statistics: per month, per year, per mile. One vehicle free, unlimited records, no ads, no account, everything stored locally with free CSV export.