Trip Fuel Cost Calculator

Find out how much fuel a journey needs and what it will cost. Works with km or miles, km/L, L/100 km or mpg, and fuel priced per liter or per gallon.

How to use the Trip Fuel Cost Calculator

  1. Enter the trip distance and choose km or miles. Pick "Round trip" if you are coming back the same way.
  2. Enter your car's fuel economy and the unit it is in: km/L, L/100 km, mpg (US) or mpg (UK). Not sure? Use the Mileage Calculator first.
  3. Enter the fuel price, whether it is per liter or per gallon, and your currency.
  4. Read the total fuel cost, the fuel needed and the cost per km or mile. Add the number of people to split the cost.

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How to calculate the fuel cost of a trip

Divide the distance by your fuel economy to get the fuel needed, then multiply by the fuel price.

Fuel needed = distance ÷ fuel economy
Fuel cost = fuel needed × price per liter (or gallon)

Example in km: a 450 km trip in a car that does 15 km/L needs 450 ÷ 15 = 30 L. At 1.60 per liter that costs 30 × 1.60 = 48.00.

Example in miles: a 300 mile trip at 30 mpg (US) needs 300 ÷ 30 = 10 gallons. At 3.50 per gallon that costs 35.00.

If your fuel economy is in L/100 km

Multiply the distance by the L/100 km figure and divide by 100. A 450 km trip at 7 L/100 km uses 450 × 7 ÷ 100 = 31.5 L. The calculator converts every unit for you, using the same factors as our MPG to L/100km converter.

What changes the real cost

Factor Typical effect on fuel use
Stop-and-go city traffic 15–30% more fuel than steady driving
Motorway speed above about 100 km/h (62 mph) Fuel use rises quickly with speed
Air conditioning About 5–10% more
Roof box, heavy load or towing About 5–25% more
Under-inflated tyres About 2–4% more

For a safe budget, use your real-world fuel economy rather than the brochure figure, and add about 10% for detours and traffic.

Frequently asked questions

How do I calculate fuel cost for a trip?

Divide the distance by your fuel economy to get the liters or gallons needed, then multiply by the fuel price. For example, 450 km ÷ 15 km/L = 30 L, and 30 L × 1.60 = 48.00.

How much fuel do I need for 100 km?

Divide 100 by your km/L figure. A car that does 12.5 km/L needs 8 L for 100 km. If your figure is in L/100 km, that number is already the answer.

How do I work out fuel cost per km?

Divide the fuel price per liter by your km/L. At 1.60 per liter and 15 km/L, each km costs about 0.107. The calculator shows this for your trip.

Does it work with mpg and gallons?

Yes. Choose miles for the distance, mpg (US) or mpg (UK) for the fuel economy, and set the price per US or UK gallon.

How do I calculate a round trip?

Choose "Round trip" under Journey and the calculator doubles the distance for you.

How do I split fuel costs between passengers?

Enter the number of people sharing the car. The calculator divides the total fuel cost equally between them.

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