How to Calculate Cost Per Mile (and What It Leaves Out)

Cost per mile is the number that decides whether a delivery route, a client visit or a contractor call-out actually makes money. The fuel-only version — distance times price per gallon divided by miles per gallon — is the one most calculators give you, and it typically understates the true figure by half or more. A cost-per-mile calculator gets you the running-cost part quickly; this guide covers what belongs in the full number.

The four cost buckets

• Fuel: distance ÷ mpg × price per gallon. Variable, easy to measure, and the only bucket most people include.
• Maintenance and tyres: servicing, wear items, repairs. Roughly proportional to distance; a national average per mile is a defensible starting point.
• Depreciation: the loss in resale value attributable to driving. Declines steeply in the first years, then flattens.
• Standing costs: insurance, road tax, finance, parking, licences. Fixed per year, but must be spread over the miles you actually drive.

The formula that survives scrutiny

Annual cost per mile = (annual fuel + annual maintenance + annual depreciation + annual standing costs) ÷ annual miles. Do not mix a per-mile fuel figure with an annual insurance figure without converting them to the same basis, which is the single most common arithmetic error in this calculation. If your mileage varies a lot by month, compute the fixed component separately and add it per job rather than per mile.

Applying it to a route or a call-out

• For a delivery zone: cost per mile times the round-trip road distance, plus time cost, compared against what the customer pays.
• For a service call-out: the same, but with the fixed component added per visit rather than apportioned by mile, because you made the trip regardless.
• For branch or territory comparisons: use the same cost basis across all branches, or the ranking is meaningless.

What the number cannot tell you

Cost per mile does not include the value of the driver's time, congestion delay, tolls, parking or the cost of an empty return leg. Those are usually larger than the running cost for short urban work, which is why a courier charge based purely on distance tends to lose money on the near jobs and overcharge the far ones. Build the per-mile figure as one line in the pricing model, not the whole model.