Cost per mile for a trucking company: the formula and a worked example

What is cost per mile and why does it decide whether a load pays?

Cost per mile is everything it costs to run your truck for a month divided by the miles you ran. Compare it to the rate per mile on a load and you know instantly whether the load makes money or loses it. It is the one number every other decision in a small carrier leans on.

The formula itself is short. Add up your fixed costs for the month, add your variable costs for the month, and divide by the miles you actually ran. The work is in getting honest inputs. Most owner-operators who think they know their number are quoting fuel plus the truck payment and forgetting insurance, tires, the trailer, the phone, the permits and the money they should be paying themselves. Those forgotten lines are exactly what turn a load that looked like $0.40 a mile of profit into a load that lost money.

The reason to do this properly is not the spreadsheet. It is the moment a broker offers $1.95 a mile for a Chicago run and you have twelve seconds to say yes or no. If your number is $1.72, that load makes $0.23 a mile and you take it. If your number is $2.08, you just agreed to lose $0.13 on every mile and you will not find out until the fuel card statement lands. MileBrain’s breakeven engine exists to answer that question while you are still typing the rate; this guide shows the arithmetic underneath it.

What counts as a fixed cost and what counts as a variable cost?

Fixed costs are the bills that arrive whether the truck moves or not: the truck and trailer payments, insurance, plates and permits, the heavy vehicle use tax, parking, phone and software. Variable costs rise with every mile: fuel, tires, maintenance and repairs, tolls, scale tickets and the driver's pay per mile.

The distinction matters because the two behave differently when you run more or fewer miles. Fixed costs get cheaper per mile the more you drive, which is why a truck that sits for a week is so expensive: the same $4,700 of bills is spread over fewer miles. Variable costs stay roughly constant per mile no matter how many you run, so they set the floor the rate can never dip under.

• Fixed, monthly: truck payment, trailer payment, liability and cargo insurance, physical damage insurance, plates and IRP, IFTA and other permits, the annual Form 2290 heavy vehicle use tax spread over twelve months, ELD subscription, phone, software, parking, and any office or accountant fee. The IRS Trucking tax center lists the federal filings that belong on this side.
• Variable, per mile: fuel, DEF, tires, preventive maintenance, repairs, tolls, scales, lumpers you are not reimbursed for, and driver pay if it is paid by the mile. Fuel is usually the single largest line and the one that moves most from quarter to quarter.
• Your own pay: put it in. If you do not pay yourself, every load looks profitable right up until you need to eat. A per-mile figure for the owner-driver belongs in variable costs; a fixed salary belongs in fixed.

OOIDA publishes a cost-per-mile worksheet with the same split if you want a second layout of the same lines. The American Transportation Research Institute’s annual Operational Costs of Trucking study is the industry benchmark for what fleets actually spend per mile, and it is useful for spotting a line you forgot, though its averages are for fleets far bigger than one truck.

How do you work out cost per mile for one truck, step by step?

List every monthly fixed bill and total it. Estimate each variable cost per mile from your own receipts, fuel first. Multiply variable cost per mile by the month's miles, add the fixed total, and divide the sum by the same miles. The result is your all-in cost per mile for that month.

Here is a complete one-truck example. These are example figures for 2026, chosen to be realistic for a single tractor-trailer running dry van in the Midwest; your own numbers will differ and only your own numbers count. The month has 9,000 total miles.

Fixed cost per mile at 9,000 miles: $4,700 ÷ 9,000 = $0.52 per mile.

All-in cost per mile: $0.52 + $1.35 = $1.87 per mile. Over the month that is 9,000 × $1.87 = $16,830 of cost. If the truck grossed $19,800 that month (an average of $2.20 a mile across every mile, loaded and empty), the profit is $2,970 after paying the driver. If it grossed $16,200 ($1.80 a mile), it lost $630 and the owner does not find out until the bills clear.

The maintenance line deserves a word. On a given month you may spend nothing on repairs; on another you spend $3,000 on a clutch. Use a reserve figure per mile from your own repair history over the last twelve months, not last month’s bill. MileBrain pulls that figure from your logged repairs automatically, which is the only way the number stays honest without a spreadsheet weekend.

How does deadhead change your breakeven rate?

Deadhead miles cost the same as loaded miles but nobody pays for them, so the cost of every empty mile is carried by the loaded ones. Divide total monthly cost by loaded miles only and the breakeven rises. At 10 percent empty miles, a $1.87 all-in cost becomes about $2.08 per loaded mile.

This is where most quick calculations go wrong. Brokers quote rates on loaded miles. Your costs accrue on all miles. If 900 of the 9,000 miles in the example were empty repositioning, the $16,830 of monthly cost has to be recovered from 8,100 loaded miles: $16,830 ÷ 8,100 = $2.08 per loaded mile. A load at $2.00 a mile looks fine against the $1.87 figure and loses money against the real one.

Two practical rules follow. First, judge a load by its rate per all miles including the deadhead to get to it: a $1,900 load that is 850 loaded miles plus 150 empty is $1.90 a mile, not $2.24. Second, a cheap load that avoids a long empty run can be the right load: 300 miles at $1.95 beats 300 miles at $0.00 every time, as long as it does not cost you a better load. The arithmetic is simple; the discipline is doing it before you say yes, every time, which is why it belongs in the app you book loads in rather than in a notebook.

How often should you recalculate it?

Recalculate cost per mile every month, and re-check the fuel line whenever diesel moves more than about twenty cents. Fixed costs change when insurance renews or a payment ends; variable costs drift with fuel prices and the age of the truck. A number from last winter can be wrong by thirty cents today.

The cheapest way to keep it current is to stop treating it as a project. Log every fuel stop with gallons and dollars, log every repair with the receipt, enter the fixed bills once and update them when they change, and let the software divide. MileBrain does exactly that: the fixed costs are entered once per truck, fuel and repair cost per mile come from your own logs, and the resulting breakeven is shown on every load as you type the rate. What it costs to run that way is on the pricing page; the first truck is free. Whatever tool you use, the test is the same: can you say your number, to the cent, for last month, without opening a spreadsheet? If not, you are booking loads on a guess.