Cost per mile (CPM) is the single most important number in your trucking company. The formula is simple: total costs ÷ total miles for the same period. If it cost you $90,000 to run your fleet last month and your trucks drove 45,000 miles — loaded and empty — your cost per mile was $2.00.
Everything else flows from that number. It tells you which rates to accept, which lanes quietly lose money, and whether that broker's "great load" actually pays for itself.
The problem is that most small fleets either never calculate it, or calculate it wrong — usually by leaving out deadhead miles or mishandling annual costs like insurance. This guide walks through the full formula, the fixed-versus-variable breakdown, a worked example for a five-truck fleet, and the mistakes that make the number lie to you.
What is the cost-per-mile formula?
Cost per mile = (fixed costs + variable costs) ÷ total miles driven, all measured over the same period.
Three rules make the formula honest:
- Use total miles, not loaded miles. Every empty mile burns fuel, tires, and hours. It belongs in the denominator.
- Use the same time period for costs and miles. Mixing last quarter's costs with this month's miles produces nonsense.
- Include every cost, even the ones you don't write a check for monthly — insurance premiums, annual plates and permits, and depreciation on trucks you own outright.
Most fleets calculate CPM monthly, then track the trailing three-month average so a single big repair bill doesn't whipsaw the number.
What are fixed costs vs variable costs in trucking?
Fixed costs stay roughly the same whether your trucks run 5,000 miles or 12,000 miles a month. Variable costs scale directly with miles. The split matters because it tells you how utilization changes your economics: every additional loaded mile spreads your fixed costs thinner.
| Category | Fixed or variable? | Notes |
|---|---|---|
| Truck & trailer payments (or depreciation) | Fixed | Applies whether you finance, lease, or own outright |
| Insurance premiums | Fixed | Annualize, then divide evenly across 12 months |
| Plates, permits, IFTA/IRP base fees | Fixed | Annualize the same way as insurance |
| Office, parking, dispatch & admin salaries | Fixed | Includes your TMS and software subscriptions |
| Fuel | Variable | Usually the largest single variable cost |
| Driver pay (per-mile or percentage) | Variable | Salaried drivers move to the fixed column |
| Maintenance, repairs & tires | Variable | Budget per mile even in months with no breakdowns |
| Tolls, scales, washouts, lumpers | Variable | Small individually, real in aggregate |
One nuance: per-mile driver pay is variable, but a salaried driver — or your own pay as an owner-operator — behaves like a fixed cost. Pick one treatment and keep it consistent, or your month-to-month comparisons break.
What does it actually cost to run a truck per mile?
The most credible industry benchmark comes from the American Transportation Research Institute. In its 2025 update of An Analysis of the Operational Costs of Trucking, ATRI reported that the average cost of operating a truck in 2024 was $2.260 per mile, a slight 0.4% decline from the prior year.
Inside that average, ATRI found:
- Non-fuel costs hit a record $1.779 per mile, up 3.6% — the highest ATRI has ever recorded.
- Fuel averaged $0.48 per mile, down 7 cents from 2023.
- Truck and trailer payments rose 8.3% to a record $0.39 per mile.
- Driver benefits climbed 4.8% to $0.197 per mile.
ATRI also found average operating margins below 2% in every sector except LTL, with the truckload sector averaging negative 2.3%. In other words: at industry-average costs and 2024-era rates, the average truckload carrier lost money. Knowing your own CPM — not the industry's — is what separates the fleets that survived from the ones that didn't.
Treat ATRI's figure as a sanity check, not a target. A small fleet running older paid-off equipment may sit well below $2.26; a fleet with new trucks and high insurance may sit above it and still be healthy if its rates match.
Worked example: cost per mile for a 5-truck fleet
Here's a hypothetical five-truck dry van fleet running 45,000 total miles in a month (9,000 per truck, including empty miles). The numbers are illustrative — plug in your own.
Fixed costs (monthly):
| Item | Monthly cost |
|---|---|
| Truck & trailer payments (5 units) | $13,000 |
| Insurance (annual premium ÷ 12) | $7,500 |
| Dispatch & admin salary | $6,000 |
| Plates, permits, software | $2,000 |
| Yard rent & miscellaneous | $1,500 |
| Total fixed | $30,000 |
Variable costs (monthly): fuel $27,000 ($0.60/mi), driver pay $29,250 ($0.65/mi), maintenance and tires $9,000 ($0.20/mi), tolls and miscellaneous $2,250 ($0.05/mi). Total variable: $67,500 — or $1.50 per mile.
Cost per mile = ($30,000 + $67,500) ÷ 45,000 miles = $2.17 per mile.
Notice the fixed-cost portion: $30,000 ÷ 45,000 = $0.67 per mile. If this fleet ran 55,000 miles instead, the fixed portion drops to about $0.55 per mile — same trucks, same insurance, roughly 12 cents per mile better economics purely from utilization.
How does cost per mile drive rate decisions and profit per load?
Once you know your CPM, every rate quote becomes arithmetic instead of gut feel. Profit per load = revenue − (total miles × CPM), where total miles include deadhead to the pickup.
Using our example fleet at $2.17 per mile: a broker offers $2,000 for an 800-mile load — $2.50 per loaded mile, which sounds comfortable. But the truck has to deadhead 100 miles to the shipper. Real math: 900 miles × $2.17 = $1,953 in cost. Profit: $47. That "$2.50 load" is nearly breakeven.
This is why per-load and per-lane profit visibility matters so much. Fleets that track profitability by truck, load, and driver catch these near-breakeven lanes in days; fleets working from a year-end P&L find out in April. CPM is also the foundation for the broader set of trucking KPIs worth tracking weekly — revenue per mile, deadhead percentage, and cost per mile move together.
What are the most common cost-per-mile mistakes?
Five errors show up constantly in small-fleet books:
- Ignoring deadhead. Dividing costs by loaded miles only inflates your apparent margin. If you run 12% empty, a "true" $2.17 CPM looks like $1.94 — and you'll price loads accordingly, straight into losses.
- Annualizing insurance wrong. Booking the whole premium (or a big down payment) in one month craters that month and flatters the rest. Divide the annual premium by 12, every time. Same for plates, permits, and IRP.
- Skipping depreciation on owned trucks. A paid-off truck isn't free — it's consuming its resale value and marching toward an overhaul. Assign it a monthly depreciation figure or your CPM understates reality.
- Using stale fuel numbers. Fuel is your biggest variable cost and it moves. Recalculate with current prices monthly.
- Forgetting the owner's pay. If you drive or dispatch, pay yourself a market wage inside the calculation. Otherwise your CPM only works while you work for free.
How do you keep cost per mile current without living in spreadsheets?
The math above takes an afternoon in a spreadsheet — once. The hard part is repeating it monthly with clean inputs: actual fuel spend, actual settlements, actual miles per truck including deadhead. That's where manual tracking breaks down, and it's the real cost of running dispatch on spreadsheets: the data exists, but nobody has time to assemble it.
A modern TMS assembles it for you. When dispatch, fuel-card data, settlements, and invoicing live in one system, cost per mile — per truck, per lane, per load — updates continuously instead of quarterly. You see the $47 load before you accept it, not after. If you're comparing systems, our 13-question TMS buyer's checklist covers what to look for.
Frequently Asked Questions
What is the formula for cost per mile in trucking?
Cost per mile equals total costs divided by total miles for the same period. Add your fixed costs and variable costs for a month, then divide by every mile your trucks ran that month, including empty miles.
What is the average cost per mile to run a truck?
The American Transportation Research Institute (ATRI) reported an industry average of $2.260 per mile for 2024 in its 2025 operational costs update. Your actual number depends on your equipment, insurance, lanes, and fuel economy, so always calculate your own.
Should deadhead miles be included in cost per mile?
Yes. Divide total costs by all miles driven, loaded and empty. If you only count loaded miles, your cost per mile looks artificially low and you will quote rates that lose money.
How often should I recalculate my cost per mile?
Monthly is ideal, quarterly is the minimum. Fuel prices, insurance renewals, and maintenance swings can move your cost per mile by 10 to 20 cents in a single quarter.
Is driver pay a fixed or variable cost?
It depends on how you pay. Per-mile or percentage pay is variable because it scales with miles. Salaried drivers and office staff are fixed costs because you pay them whether the trucks move or not.
Bottom Line
Cost per mile is total costs divided by total miles — including deadhead — over the same period. ATRI pegged the 2024 industry average at $2.260 per mile, but your number is the one that matters, and it changes monthly. Split costs into fixed and variable, annualize the big once-a-year bills, pay yourself a real wage in the math, and compare every rate quote against total-mile cost, not loaded-mile cost. Fleets that know their CPM in real time price with confidence; fleets that don't find out at tax time.
TorqueAI shows your true cost and profit per mile, per truck, and per lane — and predicts a load's profit before you accept it. Take the product tour →