Fuel cost is calculated as distance × (l/100 km) / 100 × €/l. A 100 km trip at 6.5 l/100 km and €1.60/l comes to 6.5 litres and €10.40; split between two passengers, €5.20 each.
Formula and variables
fuel_l = km × (l_per_100km / 100). cost = fuel_l × price_€_l. per passenger = cost / number of passengers. The three inputs are independent: distance sets the volume, the consumption figure sets usage, and price affects only the euro side. Consumption is given in litres per hundred kilometres, not per kilometre — hence the division by one hundred.
Which consumption figure to enter
The manufacturer's data sheet reports a cycle-measured number that is usually lower than reality. It is more reliable to measure your own: fill the tank, drive at least a couple of hundred kilometres, fill it again, then divide the litres added by the kilometres driven and multiply by one hundred. The trip computer average is a good approximation if it has accumulated over a long period since the last reset.
What raises actual consumption
City driving with stop-and-go cycles uses more than steady highway running. In winter a cold engine, short trips, winter tyres and cabin heating all add. Speed above highway pace increases air resistance with the square of velocity. A roof box, a trailer, low tyre pressure and extra load also contribute. For a specific winter trip it is worth using a figure a few percent above the summer one.
Passenger count and splitting costs
The calculator divides the total evenly between passengers. Asking passengers for fuel money is common practice, but it covers fuel only — depreciation, insurance and tyres stay outside. For reimbursing work travel in a private car the state has a separate procedure and cap, which is not the same as the bare fuel cost.
Scope and limitations
Suitable for estimating the fuel cost of a single trip or a month in a combustion-engine vehicle. The price must be entered manually — live pump prices are not fetched. It does not model driving style, load, air conditioning or winter mode, and it does not compute electric vehicles, where the units are kWh/100 km and €/kWh.
Examples
100 km, 6.5 l/100 km, €1.60/l
Fuel = 100 × 0.065 = 6.5 l. Cost = 6.5 × 1.60 = €10.40. Between two passengers ≈ €5.20 each.
Tallinn–Tartu return
About 380 km at 6.5 l/100 km gives 24.7 litres. At €1.60/l that is €39.52; between four passengers, €9.88 each.
The winter difference
Driving the same 100 km in winter at 7.8 l/100 km uses 7.8 l and costs €12.48 — the same route, almost 20% dearer. In winter months it is therefore worth using a measured winter figure rather than the data-sheet one.
Sources
- Statistics Estonia — fuel price statistics