What It Really Costs to Drive a Mile

Ask someone what it costs them to drive somewhere and they’ll think about gas. A 20-mile errand “costs a couple bucks.” That’s the cost you can feel, because you pay it in visible chunks at a pump. It’s also, for most people, not even the biggest cost of that drive. The real number — the all-in cost to put one mile on your car — is several things stacked together, and the one nobody budgets for is usually the largest.

The five buckets

Every mile you drive draws on five pools of money:

Fuel          — (annual miles / MPG) × gas price
Depreciation  — the drop in resale value over the year
Insurance     — annual premium
Maintenance   — oil, tires, brakes, repairs
Other         — registration, fees, taxes

Add the annual figures, divide by the miles you drive in a year, and you get cost per mile:

Cost per mile = (fuel + depreciation + insurance + maintenance + other) / annual miles

It’s deliberately simple math. The hard part isn’t the formula — it’s being honest about the inputs, especially the one that never shows up as a transaction.

Depreciation is the cost you don’t see

Here’s a typical owned car: 12,000 miles a year, a real 28 MPG, $3.40 gas, $1,600 insurance, $900 in maintenance, $300 in registration, and $3,000 of depreciation. Run it:

• Fuel: (12,000 ÷ 28) × $3.40 ≈ $1,457
• Depreciation: $3,000
• Insurance: $1,600
• Maintenance: $900
• Other: $300
• Total: ≈ $7,257/year → about 60 cents per mile

Fuel is barely a fifth of the total. Depreciation — the quiet erosion of what your car would sell for — is the single biggest line, and you never write a check for it. It happens whether you drive or not, it accelerates in the early years, and it’s completely invisible at the gas station. That’s exactly why people underestimate the cost of driving: they budget for the bucket they can see and ignore the one that’s bigger.

Fixed vs variable: why mileage changes everything

The five buckets don’t all behave the same way when you drive more or less.

• Variable costs — fuel and maintenance — scale with miles. Drive twice as far, spend roughly twice as much. Their per-mile cost stays flat.
• Fixed costs — depreciation, insurance, registration — are paid no matter how much you drive. Their per-mile cost falls the more you drive, because the same dollars get spread over more miles.

This is the counterintuitive result that trips people up: a car you barely drive is expensive per mile, not cheap. Take that same car and drive 6,000 miles instead of 12,000. The fixed buckets don’t shrink — you still pay insurance, still lose resale value, still register it — but now they’re spread over half the miles. Cost per mile jumps from about 60 cents to closer to 90. Drive 20,000 miles and it drops toward 45 cents.

If you barely drive, most of your cost per mile is owning the car, not using it. That’s the case for driving less and for not owning a depreciating asset you rarely move.

Run your own numbers

Enter your real annual miles, measured MPG, and the four yearly buckets. The calculator shows your cost per mile in cents, breaks it into a stacked bar so you can see which bucket dominates, and splits fixed from variable.

Does the IRS rate cover you?

The 2026 IRS standard business mileage rate is about 70 cents per mile. It exists so people who use a personal car for work can deduct or be reimbursed without tracking every receipt. It’s a nationwide average of what operating a typical car costs.

So whether it covers your real cost depends on your car:

• Below the IRS rate? Common for efficient, moderately-depreciating cars driven a lot. If you’re reimbursed at 70 cents, it more than covers your actual cost — the spread is yours.
• Above the IRS rate? Likely if you drive a fast-depreciating or expensive-to-insure vehicle, or relatively few miles. Reimbursement at the flat rate leaves you short on what driving truly costs.

Knowing your real number tells you which side of that line you’re on — useful whether you’re negotiating a mileage rate, deciding between the standard and actual deduction methods, or just deciding whether a side gig that pays “plus mileage” is actually worth it.

What the number is good for

Cost per mile is a comparison tool more than an accounting figure. A few honest uses:

1. Comparing two cars. The all-in per-mile cost — not the MPG difference alone — tells you which is genuinely cheaper to drive. A thirstier car that holds its value can easily beat an efficient one that depreciates hard.
2. Pricing a drive. A 600-mile road trip at 60 cents/mile is a $360 decision, not a “tank of gas” decision. Fuel is maybe a third of that.
3. Setting a fair rate. If you’re charging or paying per mile, your real cost is the floor.

A few honest caveats

This is a planning number, not a forensic audit of past spending. A couple of things to keep in mind:

• Repairs are lumpy. A transmission or a set of tires lands in one year, not evenly. Use a multi-year maintenance average so one big bill doesn’t distort the figure.
• Financing interest isn’t here. If the car is financed, loan interest is a real cost of driving it — model that separately.
• EVs swap the fuel bucket. For an electric car, replace gas with your annual charging cost; the rest of the structure is identical.
• Depreciation is an estimate. It’s the biggest bucket and the least precise. Use the real drop in resale value, and don’t set it to zero just because no money changed hands.

The one-paragraph version

The cost to drive a mile is fuel plus depreciation, insurance, maintenance, and registration, divided by annual miles. Fuel is the part you notice and usually the smaller part; depreciation is the part you don’t and usually the bigger one. Fixed costs make low-mileage driving expensive per mile and high-mileage driving cheap per mile. Compare your real number to the roughly 70-cent IRS rate to see whether reimbursement covers you. Run yours through the cost per mile calculator.

Related calculators

• Cost Per Mile Calculator — the five buckets, per mile, with a fixed-vs-variable split.
• MPG / Gas Mileage — your real measured MPG, the fuel bucket’s input.
• Fuel Cost — the fuel bucket in detail, per trip and per year.
• True Cost of Ownership — cost per mile plus the upfront cost of the car.
• Car Depreciation — project the value curve behind your biggest bucket.

AutoMath is an educational tool, not financial advice. Your cost per mile depends entirely on the inputs you provide — especially depreciation, which is an estimate.