How to use
Enter the distance, your car’s fuel economy and the price of gas. You’ll see how much fuel the trip takes and what it costs — and, if you enter the number of people in the car, how much each person should chip in.
Fuel economy can be in mpg (US or UK), L/100 km or km/L. With US mpg the price is per gallon; with the other units, per liter.
Formula
gallons = miles / mpg
cost = gallons × price per gallon
Example: a 300-mile trip in a car that gets 28 mpg with gas at $3.50 a gallon — about 10.7 gallons, $37.50. Split three ways, that’s $12.50 each.
FAQ
Which mpg should I use? Your real-world number rather than the sticker rating: highway driving usually beats it, while city traffic and a loaded car do worse. For a round trip, choose it in the “Trip” field and the distance is doubled.
How do I convert between mpg and L/100 km? Just pick the unit you have, or use the fuel economy converter.
Does it include tolls or wear and tear? No, only fuel. Add tolls and parking separately. The IRS mileage rate, by contrast, covers the full cost of running a car, so it’s much higher than fuel alone.