Road Trip Fuel Cost Calculator

Fuel cost = (Total miles / MPG) × Gas price per gallon. For example, a 500-mile trip in a 30 MPG car at $3.50/gallon: (500/30) × $3.50 = 16.67 gallons × $3.50 = $58.33. Divide by the number of passengers to get the per-person cost. Add a 10% buffer for detours and city driving in unfamiliar areas.

For distances under 400–500 miles with 2+ passengers, driving is almost always cheaper. For 1,000+ miles, flying can be comparable or cheaper once you account for time, airport fees, and parking. The break-even depends heavily on gas prices, airline fares, number of passengers, and whether you need a rental car at the destination. This calculator provides rough flight estimates for context.

A 1,000-mile round trip in a 30 MPG car uses about 33 gallons. A 500-mile one-way trip uses 17 gallons. Plan for fill-ups every 300–400 miles on a standard 12-15 gallon tank. In remote areas or before mountain passes, fill up earlier than usual — stations can be 100+ miles apart in some western states.

Burning one gallon of gasoline produces 19.6 pounds (8.9 kg) of CO2. A 500-mile trip at 30 MPG uses 16.7 gallons and emits about 327 lbs (148 kg) CO2. Split among 4 passengers, that is 82 lbs per person — comparable to a short domestic flight at the same distance. Carpooling significantly reduces the per-person carbon footprint.