Fleet cost per km: how to calculate vehicle running costs

Fleet cost per km is the total cost of running a vehicle for a period divided by the kilometres it drove in that period. Count both fixed costs (depreciation or lease, financing, insurance, taxes) and variable costs (fuel or energy, maintenance, tyres, repairs). A van that costs €12,600 a year and covers 30,000 km costs €0.42 per km.

Cost per km = total vehicle costs for the period ÷ kilometres driven in the period

Use a full year where you can, so that annual insurance, seasonal tyres and occasional repairs are all included. The same calculation over a vehicle's whole life gives its total cost of ownership (TCO) per km. If you work in miles, divide by miles instead: the same van covers about 18,641 miles, so it costs about €0.68 per mile.

Fixed and variable vehicle costs

Fixed costs stay roughly the same however much the vehicle is driven. Variable costs grow with every kilometre. Both belong in cost per km.

Registration fees, vehicle taxes and the tax treatment of company vehicles differ from country to country, so check the rules in your country with your accountant. Driver wages are usually counted as labour rather than as a vehicle cost.

The split matters because fixed costs per km fall as a vehicle is used more. A van that stands in the yard half the week still pays its full insurance and depreciation.

Worked example: one delivery van over a year

A business bought a delivery van for €32,000 in cash and expects to sell it for €8,000 after 5 years. This year the van drove 30,000 km and used 8.5 litres of diesel per 100 km, at an average price of €1.60 per litre.

Straight-line depreciation = (purchase price − residual value) ÷ years = (€32,000 − €8,000) ÷ 5 = €4,800 a year

Fuel cost = km × l/100 km ÷ 100 × price per litre = 30,000 × 8.5 ÷ 100 × €1.60 = 2,550 litres × €1.60 = €4,080

Cost per km = €12,600 ÷ 30,000 km = €0.42, of which €0.22 is fixed (€6,600 ÷ 30,000) and €0.20 is variable (€6,000 ÷ 30,000).

Now suppose the same van drives only 20,000 km. Fixed costs stay at €6,600, which is €0.33 per km, and variable costs stay at about €0.20 per km, so the cost per km rises to €0.53. Low use makes a vehicle expensive per km even when nothing is wrong with it.

The van was paid in cash, so there is no financing line; with a loan, add the year's interest. Depreciation here is the real loss of value; the depreciation used for tax can follow different rules.

Fuel consumption formula

Fuel consumption (l/100 km) = litres ÷ kilometres × 100

The most reliable method is tank to tank: fill the tank completely, note the odometer, and at the next full fill-up divide the litres added by the kilometres driven since. If the van takes 68 litres after 800 km, consumption is 68 ÷ 800 × 100 = 8.5 l/100 km. Over the whole year the same formula gives 2,550 ÷ 30,000 × 100 = 8.5 l/100 km.

Comparing vehicles and spotting outliers

Cost per km becomes useful when you compare vehicles that do similar work. Here are three vans of the same model on similar delivery routes:

The fleet figure is total cost ÷ total km: €36,800 ÷ 77,000 km ≈ €0.48. Do not simply average the three per-km figures, which gives about €0.49 and lets a little-used vehicle weigh as much as a busy one.

Van 3 costs about a quarter more per km than the fleet average. To find out why, split its cost into the same lines as the worked example and compare each line per km with the other vans:

• Fuel use is high (10.4 against 8.5–8.7 l/100 km): check tyre pressure, driving style, idling, the route, and whether every fuel receipt really belongs to this van.
• Maintenance or repairs are high: an older vehicle or a recurring fault; look at the maintenance log.
• Kilometres are low: fixed costs are spread over fewer km; check whether the van is needed every day.

Compare each vehicle with itself as well. A cost per km that rises quarter after quarter is an early sign of trouble.

Electric and combustion vehicles

For an electric vehicle, replace fuel with electricity:

Energy cost per km = kWh/100 km × price per kWh ÷ 100

An electric van using 22 kWh/100 km at €0.25 per kWh costs 22 × €0.25 ÷ 100 = €0.055 per km in energy. The diesel van above costs 8.5 × €1.60 ÷ 100 = €0.136 per km. Energy is only part of the picture: electric vehicles often cost more to buy, which raises depreciation or the lease, while routine servicing tends to be simpler. Compare the total cost per km over the years you plan to keep the vehicle, using the price you really pay to charge, which differs between your own premises and public chargers. Incentives and taxes for electric vehicles depend on the country.

The data you need and how to collect it

Cost per km is only as good as the records behind it. For every vehicle you need:

• Fuel receipts or charging records: date, vehicle, litres or kWh, price and amount, with the odometer reading at every fill-up.
• Odometer readings: at least at the start and end of each month, so that kilometres are measured, not estimated.
• Maintenance log: every service, repair and tyre change, with date, kilometres, workshop and cost.
• Trip logs or telematics: where the vehicle went, how far, and which kilometres were business or private.
• Driver assignments: who had which vehicle and when, so fuel use, fines and damage can be traced to a person.
• Fixed-cost documents: purchase or lease contract, financing, insurance policies and registration, with their renewal dates.

Link every cost to a vehicle: a fuel receipt or workshop invoice that is not tied to a vehicle cannot be counted in its cost per km. Capture receipts when they happen, with a photo or scan, rather than collecting them at month end.

How to reduce fleet costs

1. 1Service on schedule. Preventive maintenance costs less than breakdowns, towing and days off the road.
2. 2Check tyre pressure regularly. Under-inflated tyres raise fuel use and wear out sooner.
3. 3Improve driver behaviour. Speeding, harsh braking and acceleration, and long idling burn fuel and wear brakes and tyres. Share each driver's figures and coach those well above the average.
4. 4Plan routes. Fewer kilometres reduce every variable cost at once; combine trips and avoid peak traffic where you can.
5. 5Right-size the fleet. A vehicle used two days a week has a high fixed cost per km. Share vehicles through bookings, sell those you rarely need, and choose the smallest vehicle that does the job.
6. 6Set private-use rules. Decide whether private trips are allowed, record them and agree who pays. Tax rules for private use of company vehicles differ by country, so check them with your accountant.
7. 7Control fuel purchases. Compare the litres bought with the tank size and the kilometres driven, and investigate fill-ups that do not add up.
8. 8Replace vehicles whose cost per km keeps rising, using the rule in the next section.

Keep or replace: when a vehicle costs too much

An older vehicle loses less value each year, but its repairs, downtime and fuel use tend to rise. The simple rule:

Replace a vehicle when its expected cost per km for next year is higher than the expected cost per km of a replacement over the same distance.

Van 3 from the table is due a new clutch and new tyres next year, and you estimate its total cost at €14,300 for 22,000 km, or €0.65 per km. A new van like Van 1 would cost €6,600 in fixed costs plus about €0.20 × 22,000 km = €4,400 in variable costs, so €11,000 in total, or €0.50 per km. Keeping Van 3 would cost about €3,300 more next year, so replacing it makes sense.

Before you decide, take into account what the old vehicle would sell for now (it will be worth less next year), the cost of downtime when it breaks down, and how the purchase or lease affects your cash. A cash flow forecast shows whether you can pay for the new vehicle without strain.

Common mistakes

1. 1Counting only fuel. In the example above, fuel is only about a third of the total cost.
2. 2Using a period that is too short. One month can include an annual insurance premium or miss a big repair; use a year or a rolling 12 months.
3. 3Estimating kilometres. Without odometer readings, the cost per km is a guess.
4. 4Averaging per-km figures instead of dividing total cost by total kilometres.
5. 5Comparing unlike vehicles, such as a small city car with a large van, or a van on long motorway trips with one on city deliveries.
6. 6Ignoring resale value. The cheapest vehicle to buy is not always the cheapest per km if it loses value fast or uses more fuel.
7. 7Leaving costs unassigned. Fines, damage and fuel that are not linked to a vehicle and a driver disappear from the analysis.

How Clientlly helps

In Clientlly every vehicle has a detailed profile with its drivers and assignments, reservations and availability, maintenance schedules and records, inspections, incidents and violations. Fuel entries can be added by scanning the fuel receipt, fuel analytics let you compare consumption between vehicles, and the fleet dashboard gives you an overview of the whole fleet. Predictive maintenance helps you plan servicing, trip logs show how each vehicle is used, and legal documents, insurance and expiry tracking keep renewals in view. When telematics devices are connected, you also get GPS trip replay, live tracking, geofences, alerts and driver scores. See the fleet and motor pool module.