Fuel Cost Calculator
Estimate the fuel cost of a trip from distance, vehicle mileage and fuel price — total litres needed, total cost and cost per person when shared.
The calculation
Litres = distance (km) ÷ efficiency (km/L) · Cost = litres × price per litre
Miles are converted to kilometres (×1.609), and L/100km or US MPG efficiencies are converted to km/L first
(km/L = 100 ÷ L/100km; km/L = MPG × 0.425).
Worked example
300 km at 15 km/L, fuel 1.60/L: 300 ÷ 15 = 20 litres; 20 × 1.60 = 32.00 total,
about 0.11 per km. Shared among four people that's 8.00 each — usually far cheaper than four train tickets,
which is why carpooling wins on cost for full cars.
Cutting the number down
- Highway speeds matter: most cars use 15–25% more fuel at 120 km/h than at 95 km/h.
- Correct tyre pressure alone is worth ~3%.
- Roof boxes can add 10–25% at speed — remove them when unused.
Frequently asked questions
How do I calculate the fuel cost of a trip?
Fuel needed = distance ÷ your vehicle’s km per litre; cost = litres × price per litre. A 300 km trip at 15 km/L with fuel at 1.60/L needs 20 L and costs 32.00.
What mileage should I enter?
Your real-world figure, not the brochure number — most cars achieve 10–20% worse than official ratings. Fill the tank, drive normally until the next fill, and divide kilometres driven by litres refilled.
How do we split fuel fairly on a shared trip?
Divide the total fuel cost by the number of people, driver included — this calculator shows the per-person share. Some groups add a little extra for the driver’s wear-and-tear, which is a fair convention for long trips.
Does this include tolls and other costs?
No — it covers fuel only. Add tolls, parking and (for true cost) depreciation separately. Fuel is typically only about half the real per-km cost of running a car.