The calculation
US mode: gallons = miles ÷ MPG, cost = gallons × price. Metric mode: liters = km × (L/100km) ÷ 100. The split divides total cost evenly among passengers — the fair-share number for group trips.
Real-world adjustments
Highway speeds, roof boxes, and mountain routes can raise consumption 10–30% above your car's rated economy. If the trip is mostly highway at speed, knock a few MPG off (or add ~1 L/100km) for a safer estimate.
Frequently asked questions
How do I estimate gas cost for a trip?
Divide the distance by your car's MPG to get gallons, then multiply by the price per gallon — exactly what this tool does.
What's a typical fuel economy to assume?
Around 25–30 MPG (8–9.5 L/100km) for a modern gasoline sedan; SUVs and trucks are lower.
Should the driver pay less when splitting?
Many groups exempt the driver or count the car's wear via a mileage rate; this tool splits fuel evenly, which is the simplest convention.