Fuel Cost Calculator
Use our free fuel cost calculator to estimate how much you will spend on petrol or diesel for any trip. Enter the distance, your car's fuel consumption rate, and the current fuel price to instantly see how many litres (or gallons) you need and the total journey cost. The tool supports both metric (litres per 100 km) and imperial (miles per gallon) units, making it useful whether you drive in Europe, the US, or elsewhere.
Fuel costs are one of the most significant recurring expenses for car owners. According to industry data, the average European passenger car consumes around 6–8 litres per 100 km, while American vehicles average around 25–30 MPG. By calculating fuel costs before a trip, you can better plan your travel budget, decide whether to refuel before a long journey, and compare the real cost of driving versus public transport or car-sharing.
Frequently Asked Questions
How is fuel cost calculated?
Fuel cost = (distance ÷ 100) × fuel consumption rate × fuel price per litre (metric). In imperial: fuel needed (gallons) = distance (miles) ÷ MPG, then total cost = gallons × price per gallon.
What is L/100km?
L/100km (litres per 100 kilometres) is the most common fuel efficiency metric in Europe and most of the world. It tells you how many litres of fuel your car consumes to travel 100 kilometres. A lower number means better fuel efficiency.
What is MPG?
MPG (miles per gallon) is the fuel efficiency unit used in the United States and United Kingdom. It represents how many miles a vehicle can travel on one gallon of fuel. A higher MPG number means better fuel efficiency — the opposite of L/100km.
How do I convert L/100km to MPG?
To convert L/100km to US MPG: divide 235.21 by the L/100km value. For example, 8 L/100km = 235.21 ÷ 8 ≈ 29.4 MPG. To convert US MPG to L/100km: divide 235.21 by the MPG value.
What is the average fuel consumption of a car?
The average new passenger car in Europe consumes about 6–7 litres per 100 km. SUVs and larger vehicles typically use 8–12 L/100km. In the US, the average new car achieves around 28–30 MPG, while trucks and SUVs average 20–25 MPG.
Does driving speed affect fuel consumption?
Yes, significantly. Fuel consumption increases sharply above 90–100 km/h (55–62 mph) due to aerodynamic drag. Driving at 120 km/h can use 20–30% more fuel than at 90 km/h. Smooth, steady driving at moderate speeds is most fuel-efficient.
How does tyre pressure affect fuel costs?
Under-inflated tyres increase rolling resistance, which raises fuel consumption by up to 3% per 10% tyre pressure deficit. Keeping tyres properly inflated as per manufacturer recommendations can noticeably reduce fuel costs over time.
Is diesel cheaper to run than petrol?
Diesel engines are typically more fuel-efficient (20–30% better L/100km), so they can be cheaper per kilometre even if diesel costs more per litre. However, petrol cars have lower purchase and maintenance costs, so the break-even depends heavily on annual mileage.
How can I reduce fuel costs?
Key strategies include: driving smoothly without harsh acceleration or braking, maintaining steady speeds, keeping tyres properly inflated, removing unnecessary weight, using cruise control on motorways, avoiding excessive idling, and keeping up with regular car servicing.
What is the difference between city and highway fuel consumption?
City driving typically uses 20–40% more fuel than highway driving due to frequent stopping and starting. Fuel efficiency is worst in stop-and-go traffic because the engine idles and accelerates repeatedly. Hybrid cars narrow this gap significantly by recovering energy during braking.
How do I calculate the cost of a round trip?
Simply enter the total round-trip distance in the distance field. For example, if your destination is 150 km away and you return the same way, enter 300 km. The calculator will show the total fuel needed and cost for the complete journey.