Fuel cost & trip calculator

Fuel cost comes down to three numbers: how far you drive, how many miles you get per gallon, and what a gallon costs where you fill up. The calculator above multiplies them out for a single trip, a month and a year, and splits a road-trip bill between passengers if you like.

1. 1Gallons used = distance ÷ fuel economy (MPG).
2. 2Trip cost = gallons used × price per gallon.
3. 3Cost per mile = price per gallon ÷ MPG.
4. 4Yearly cost = miles per year × cost per mile.

For example, 300 miles at 30 mpg uses 10 gallons. At $3.50 a gallon that's $35, or about 11.7 cents a mile.

When you pick your car, we fill in its official rating from the EPA's fueleconomy.gov (opens in a new tab) data, which covers model years from 1984 on. You can switch between the combined, city and highway ratings:

• Use highway for long interstate trips at steady speeds.
• Use city for short, stop-and-go driving.
• Use combined (55% city, 45% highway in the EPA's weighting) for a typical mix.

EPA ratings come from standardized lab tests, so your real-world number can differ, especially at high speeds, with a roof box or trailer, in cold weather, or with lots of idling. If you track fill-ups, your own average is the best number to use; the MPG calculator works it out.

• Use the price where you'll actually buy fuel. Prices can vary a lot between states and between highway and in-town stations.
• Add a margin for detours and for speed: fuel economy usually drops at sustained highway speeds above the speed the car was tested at.
• Check the fuel type. Cars that require premium cost more per gallon; see the regular vs premium calculator.
• Going electric? Compare charging costs with the EV vs gas calculator.

Results are estimates from the numbers you enter and, where noted, EPA ratings. Not financial advice. Page updated Oct 5, 2026.