Fuel Cost Calculator
Estimate how much fuel a journey needs and what it will cost, using metric or imperial units for distance, fuel economy and price.
Result
Enter your values and select Calculate to see the result.
How to use this calculator
- Enter the trip distance in kilometers or miles.
- Enter your vehicle’s fuel efficiency and its unit. US and UK MPG are different, so pick the right one.
- Enter the fuel price and whether it is per liter, US gallon or UK gallon.
- Tick Round trip to double the distance.
Formula
The calculator first works out the liters needed:
- L/100 km: liters = km × efficiency ÷ 100
- km/L: liters = km ÷ efficiency
- US MPG: liters = miles ÷ MPG × 3.785411784
- UK MPG: liters = miles ÷ MPG × 4.54609
Then cost = fuel volume (in the price unit) × price.
Worked example
Metric
420 km at 6.5 L/100 km with fuel at 1.80 per liter.
Fuel: 420 × 6.5 ÷ 100 = 27.3 L. Cost: 27.3 × 1.80 = 49.14.
US units
300 miles at 28 MPG (US) with fuel at 3.60 per US gallon.
Fuel: 300 ÷ 28 = 10.71 gallons. Cost: 38.57.
Assumptions and limitations
- This is an estimate based on the values you enter. Real consumption depends on speed, traffic, load, terrain, tyre pressure, weather and air-conditioning use.
- Currency is not converted; the cost is in whatever currency your fuel price uses.
- Electric vehicles are not covered.
Frequently asked questions
How do I convert MPG to L/100 km?
For US MPG, L/100 km = 235.215 ÷ MPG. For UK MPG, L/100 km = 282.481 ÷ MPG.
How do I find my car’s real fuel economy?
Fill the tank, reset the trip meter, drive normally, then refill. Divide the fuel added by the distance driven (× 100 for L/100 km).