Fuel Cost Calculator
Estimate your trip fuel cost based on distance, fuel efficiency, and fuel price.
Trip Details
Estimated Trip Cost
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How the fuel cost estimate is calculated
The calculator divides trip distance by your vehicle fuel efficiency to get the volume of fuel consumed, then multiplies that volume by the price you pay per litre or per gallon. In metric mode the formula is litres = distance in kilometres divided by one hundred, multiplied by the L/100 km rating. In US mode it is gallons = miles divided by miles per gallon. Because the two efficiency conventions run in opposite directions, a lower L/100 km number and a higher MPG number both mean a more efficient vehicle, so make sure the unit selector matches the figure printed in your manual before comparing results between cars.
Why real-world fuel use differs from the sticker rating
Published efficiency ratings come from standardised laboratory drive cycles at moderate speed with no cargo, no roof rack, no air conditioning and a warm engine. Real trips rarely match those conditions. Aerodynamic drag rises with the square of speed, so sustained motorway driving above roughly 110 km/h burns noticeably more fuel per kilometre than the rating suggests. Cold starts, short urban journeys, hills, headwinds, under-inflated tyres, heavy loads and roof boxes each add a few percent. A practical approach is to derive your own efficiency figure from two or three full-tank fill-ups, then use that number here instead of the manufacturer rating.
Planning a trip budget
For a round trip, enter the total distance in both directions rather than one leg. When several people share a car, divide the calculated total by the number of passengers to get a fair per-person contribution, a figure commonly used for ride sharing and expense claims. Fuel is only one component of the cost of driving: many tax authorities publish a per-kilometre or per-mile reimbursement rate that also covers tyres, servicing, depreciation and insurance, and that rate is typically two to three times the pure fuel cost shown here.
Cite this page
UnitConvertLab. (2026). Fuel Cost Calculator. UnitConvertLab. Retrieved from https://unitconvertlab.com/tools/fuel-cost-calculator