Fuel Cost Calculator
Free gas & fuel trip cost calculator — total fuel cost, litres or gallons used, and cost per mile or km, with round-trip and split options.
Everyday Uses
Trip budgeting
Estimate the fuel bill for a road trip or commute before you set off.
Mileage claims
Work out the cost per mile or km to log expenses or reimburse driving.
Split the cost
Divide the fuel bill fairly between everyone sharing the ride.
Compare cars
See how much a more efficient vehicle would save on the same route.
Frequently Asked Questions
How do you calculate the fuel cost of a trip?
First work out the fuel used, then multiply by the price. In imperial units, fuel (gallons) = distance ÷ MPG; in metric, fuel (litres) = distance ÷ 100 × (L/100km). Then cost = fuel × price per gallon or litre. For a 300-mile trip at 32 MPG with fuel at $3.50/gallon: 300 ÷ 32 = 9.375 gallons × $3.50 = $32.81.
How do I calculate cost per mile or km?
Divide the total fuel cost by the distance. If a 300-mile trip costs $32.81 in fuel, that is $32.81 ÷ 300 ≈ $0.11 per mile. This calculator shows cost per mile or per km automatically, which is handy for comparing vehicles or claiming mileage.
How do I convert MPG to L/100km?
For US MPG, L/100km = 235.215 ÷ MPG. So 32 US MPG ≈ 7.35 L/100km. Switch this calculator to metric mode to enter L/100km directly. Note that UK gallons differ from US gallons, so confirm which your MPG figure uses.