Fuel Cost Calculator

How to use the calculator

1. Enter the one-way distance in miles. A route planner or your trip odometer gives you this.
2. Leave the unit on mpg and enter your car's miles per gallon. Use your own measured figure if you have one; otherwise use the EPA combined rating from the window sticker or fueleconomy.gov.
3. Enter the price per gallon you expect to pay.
4. Tick round trip if you are driving back the same way.
5. Enter how many people are sharing the cost. The per-person amount appears only when there are two or more.

Driving abroad? Switch the unit to L/100 km or km/L: the distance is then read in kilometers and the price per liter.

How the cost is calculated

The calculator first works out how much fuel the trip needs, then multiplies by the price:

gallons = miles ÷ mpg
trip cost = gallons × price per gallon

• Round trip doubles the distance before anything else is calculated.
• Cost per mile = trip cost ÷ total miles. It is handy for comparing cars or for pricing a regular commute.
• Per person = trip cost ÷ number of people.
• With L/100 km, liters = km × L/100 km ÷ 100; with km/L, liters = km ÷ km/L.

All figures use U.S. gallons (3.785412 liters, per NIST). The result covers fuel only: tolls, parking and wear on the car are not included, and the calculator assumes the same mpg for the whole drive.

Examples

Prices below use $4.35 per gallon, close to the U.S. average for regular gasoline of $4.354 reported by the EIA for the week of October 5, 2026. Use the price at your own station.

1. A 300-mile drive at 30 mpg

You burn 10 gallons, so the trip costs $43.50, or 14.5 cents per mile.

2. Road trip for four, 450 miles each way

With round trip ticked, the total distance is 900 miles. At 25 mpg the car uses 36 gallons for $156.60, which is $39.15 per person.

3. A year of driving: SUV vs. hybrid

At 12,000 miles a year, a 22 mpg SUV uses about 545.5 gallons and costs $2,372.73. A 35 mpg car covers the same miles on 342.9 gallons for $1,491.43, about $881 less.

Reading the result

The answer is only as good as the mpg you enter. EPA ratings come from standardized tests and are meant for comparing vehicles, so your real mileage can be higher or lower depending on how and where you drive and on the condition of the car. According to fueleconomy.gov, aggressive driving can cut gas mileage by roughly 15% to 30% at highway speeds and 10% to 40% in stop-and-go traffic, and mileage usually drops quickly above 50 mph. For a long highway trip at speed, or a loaded car with a roof box, it is sensible to budget a little extra.