Road Trip Fuel Cost Calculator

Fuel is typically the largest variable cost on a road trip, and it varies dramatically based on vehicle efficiency, distance, and fuel prices. This calculator gives you an accurate estimate so you can budget properly and compare alternative routes or vehicles.

The Fuel Cost Formula

Fuel Used = Distance / Fuel Economy

Total Cost = Fuel Used × Price Per Unit

In imperial (US):

• Distance in miles, economy in MPG (miles per gallon)
• Gallons = Miles / MPG
• Cost = Gallons × Price per gallon

In metric:

• Distance in km, economy in L/100km (liters per 100 km)
• Liters = Distance × L/100km / 100
• Cost = Liters × Price per liter

Unit Conversion

Two of these are commonly written the wrong way round, so here they are in both directions:

The imperial one catches people out. A UK gallon is 4.546 litres against the US 3.785, so a car advertised at 40 mpg in Britain does about 33 mpg by American measurement. The car did not change; the gallon did. If you are reading a British review of an American car, or the reverse, that is a 20% error waiting to happen.

Typical Fuel Economies

Fuel Price Averages (typical ranges)

US regular gasoline: $3.00–$4.50 per gallon European gasoline: €1.50–€2.00 per liter Australian petrol: A$1.70–A$2.30 per liter Canadian gasoline: C$1.40–C$2.00 per liter

Additional Road Trip Costs

Don’t forget to budget for: tolls (can be significant on US East Coast and European motorways), rest stop food and drinks, parking fees at destinations, and any wear items (tires, oil).