Estimate how much fuel a trip will use and what it will cost, in miles and gallons or kilometers and liters, and split the cost between passengers.
How to calculate fuel cost
Miles and gallons: Fuel = distance ÷ MPG
Kilometers and liters: Fuel = distance × L/100 km ÷ 100
Cost = fuel × price per gallon or liter
Worked examples
- A 300-mile trip in a car that gets 28 MPG uses about 10.71 gallons. At $3.50 a gallon, that is $37.50.
- A 500 km trip in a car using 7 L/100 km needs 35 liters. At 1.80 a liter, the fuel costs 63.00.
Where to find your fuel economy
Use your car's trip computer, or fill the tank, reset the trip meter, drive normally, then divide the miles driven by the gallons needed to refill. Highway driving is usually more efficient than city driving, so use a highway figure for road trips.
Tips to save fuel
- Keep tires properly inflated.
- Drive at steady speeds and avoid hard acceleration. Fuel use rises quickly above about 60 mph.
- Remove roof racks and extra weight when not needed.
- Compare fuel prices along your route before you leave.
Frequently asked questions
How do I convert MPG to L/100 km?
Divide 235.2 by the MPG (U.S. gallons). 28 MPG is about 8.4 L/100 km. Use the unit converter for other conversions.
Does this include tolls or wear?
No. For the full cost of driving, add tolls, parking and roughly 10 to 20 cents per mile for maintenance and tires.
Related tools
Results are estimates for planning and education only. They are not financial, tax, legal or medical advice. Check important numbers with a qualified professional.