Fuel Cost Calculator
Work out how much fuel a trip will cost. Enter the distance, your vehicle's fuel economy (in litres per 100 km), and the price per litre to get the total fuel cost, litres used, and cost per kilometre.
How this calculation works
Litres used = distance ÷ 100 × fuel economy (L/100km). This scales your car's consumption rate to the actual trip length.
Total fuel cost = litres used × price per litre. This is the amount you can expect to spend filling up for the trip.
Cost per kilometre = total cost ÷ distance. It is a handy figure for comparing trips, vehicles, or splitting costs with passengers.
Worked example
Fuel economy of common trip lengths
Using a mid-size car averaging 7 L/100km at a fuel price of 1.60 per litre, here is roughly what different trip distances cost:
| Distance | Litres used | Estimated cost |
|---|---|---|
| 50 km (city commute) | 3.5 L | 5.60 |
| 200 km (day trip) | 14 L | 22.40 |
| 500 km (road trip) | 35 L | 56.00 |
| 1,000 km (long haul) | 70 L | 112.00 |
What changes real-world fuel economy
- Driving style: gentle, gradual acceleration and early braking can cut consumption by 15% or more compared to aggressive driving.
- Speed: drag rises sharply above 100 km/h, so highway cruising speed has an outsized effect on economy.
- Tyre pressure: under-inflated tyres increase rolling resistance; check pressure monthly against the door-jamb sticker.
- Weight and drag: roof boxes, bike racks, and unnecessary cargo both add weight and disrupt airflow.
- Traffic and terrain: stop-start city traffic and hilly routes use noticeably more fuel than steady highway driving.
- Vehicle maintenance: worn spark plugs, low tyre pressure, and dirty air filters all quietly raise consumption.
Fuel cost vs. public transport
For a solo commuter, public transport is often cheaper per trip than driving once fuel, parking, and wear are counted, especially in cities with tolls or congestion charges. But once a car carries two or more people, the fuel cost per person can undercut individual transit fares, particularly on routes transit does not serve directly.
For a fair comparison, add parking and tolls to the fuel cost above, then divide by the number of occupants to get a genuine per-person figure to weigh against transit ticket prices.