Fleet TCO explained: how to calculate cost per kilometre

Ask what a vehicle costs and the first file anyone opens is the fuel receipts. Fuel is the most visible line: it is paid every week, it has an invoice, it is easy to argue about. It also does not explain what the vehicle actually costs the company.

Total cost of ownership reduces every line you pay while the vehicle sits in the fleet to a single number. Below is how that number is built, which items usually go missing, and what decisions the result can carry. The method works on paper — all it needs is a few records kept consistently.

What is total cost of ownership?

TCO covers every cost the vehicle creates while you own it — insurance, road tax, depreciation, fuel, tolls, servicing, tyres and incidents — rather than what you paid to buy it.

The word "total" is the point. Purchase price is paid once and argued about at the moment of the decision; TCO is the figure worth arguing about for the life of the vehicle. Two vehicles can carry the same sticker price and end four years apart on total cost.

Which cost lines make up a vehicle?

Splitting the lines into three buckets makes both the arithmetic and the conversation easier, because the buckets behave differently. One runs whether or not the vehicle moves, one grows only with kilometres, and one cannot be predicted.

1. Fixed costs — they run even in the yard

• Insurance — the annual premium, divided across months.
• Road tax and registration — annual, spread over the period regardless of when it is paid.
• Depreciation — the line most often skipped. No invoice arrives, so it does not feel like a cost, but it leaves your pocket on the day you sell.
• Inspection, licensing and subscription fees — small amounts, regular repetition.

2. Variable costs — they grow with kilometres

• Fuel or charging — measured consumption, not the catalogue figure.
• Tolls — bridges, tunnels and motorway gates, plus country vignettes on cross-border routes.
• Servicing and tyres — both are driven by distance. Allocating a per-kilometre share gives a truer result than dividing the annual budget by twelve.

3. Incident costs — unpredictable but recurring

• Accidents and damage — the excess, repairs outside the policy, and the days the vehicle spends off the road.
• Traffic fines and parking — individually small, collectively surprising at year end.
• Unplanned repairs — everything that is not scheduled maintenance.

How do you calculate cost per kilometre?

Divide the total cost for the period by the kilometres driven in that period. If fixed costs are annual, take the share that falls into the period first, then add.

Worked example: the monthly cost of a van

The table below is an illustrative scenario — the figures should come from your own fleet. Diesel is taken at approximately 73.50 ₺ per litre for July 2026; because fuel prices move weekly, the calculation has to be repeated each period at the current price.

Look only at the fuel invoice for the same vehicle and the figure is ₺5.51/km. A fleet that tracks fuel alone is therefore seeing roughly half of what the vehicle costs. The missing half is not lost — it sits under other accounts, in the policy folder, and in the depreciation that surfaces on the day of sale.

Why is the least used vehicle the most expensive one?

Fixed costs ignore distance. At 900 km a month the same insurance, the same road tax and the same depreciation still run, so the cost per kilometre climbs.

Because its total invoice is smaller, the second vehicle is usually filed under "no problem". Yet every kilometre it carries is the most expensive kilometre in the fleet. Once that table is visible, the questions change: moving the vehicle to another department, switching to short-term rental, or disposing of it all come onto the table.

How often should TCO be calculated?

Monthly is enough, but no single month should decide anything. The month a vehicle goes in for major service will push its cost per kilometre to an artificial peak. For decisions, a three-month average is safer, and for comparison, the same period for vehicles doing the same job.

Two events justify recalculating without waiting: an insurance renewal, which resets the fixed cost base, and a clear move in fuel prices, which shifts the variable side.

Five common mistakes

1. 1Leaving depreciation out. It is the only large line without an invoice, so it never reaches the table — and when the vehicle is sold, the loss is written off as "that is the market".
2. 2Booking an annual cost to the month it was paid. Put the whole insurance premium in January and January's cost per kilometre means nothing. Annual lines have to be spread.
3. 3Calculating fuel from the catalogue figure. The gap between declared and measured consumption turns into a several-thousand deviation over a year.
4. 4Not reading odometers consistently. A wrong denominator makes the division wrong; the kilometre record matters as much as the fuel record.
5. 5Dissolving vehicles into an average. "Our fleet average is ₺9/km" leads to no decision at all. Decisions are made per vehicle, by looking at the ones that sit away from the average.

What is the number actually for?

Cost per kilometre is not a report line on its own; it is an input to several decisions:

• Pricing a job — knowing what the trip actually costs before you quote it.
• Own versus lease — comparing the monthly equivalent cost against a rental offer.
• Replacement timing — as the repair share grows, cost per kilometre rises, and at some point the curve crosses the cost of leasing or of a newer vehicle.
• Departmental budgets — a gap in cost per kilometre between two teams doing the same work is a signal worth discussing.

The hard part is not the arithmetic; it is keeping the data together. While the insurance policy lives in one folder, the fuel receipts in another file and the odometer reading on a driver's phone, the table has to be rebuilt from scratch every month. The method never changes — what makes the difference is records accumulating in one place, in one format.