Trip Fuel Cost Calculator

Enter the distance, your car's fuel economy and the price of gas to see how much the trip will cost – in total and per passenger.

Your details

mi
mpg
$/gal

Result

Total fuel cost–
  • Fuel needed–
  • Cost per person–
  • Cost per mile–

Results are estimates for information only and are not financial, tax or legal advice.

How the trip fuel cost is calculated

The calculator first works out how many gallons the trip needs, then multiplies that by the price per gallon:

Gallons = Distance ÷ MPG
Fuel cost = Gallons × Price per gallon

If you tick round trip, the distance is doubled. The cost per person is simply the total divided by the number of people sharing the ride.

Worked example

A 300-mile drive in a car that averages 30 mpg needs 300 ÷ 30 = 10 gallons. At $3.20 per gallon the trip costs $32.00. Driven there and back it is $64.00, or $16.00 each for four people.

Tips for an accurate estimate

  • Use your real MPG. The EPA sticker is a guide; your trip computer or a fill-up log (miles driven ÷ gallons added) is more accurate.
  • Highway vs. city. Most cars use noticeably less fuel at steady highway speeds than in stop-and-go traffic. Above about 60 mph, consumption rises quickly.
  • Load and weather. Roof boxes, a full trunk, towing, cold weather and air conditioning can all cut fuel economy by 10–25%.
  • Price differences. Gas prices vary a lot between states and stations. Use the price where you expect to fill up.

What this calculator does not include

Only fuel is counted. Tolls, parking, wear and tear, tires and depreciation add to the real cost of driving. The IRS standard mileage rate is a useful benchmark for the full cost per mile of owning and running a car.

Frequently asked questions

How do I find my car's MPG?

Fill the tank, reset the trip meter, drive normally, then fill up again. Divide the miles driven by the gallons needed to refill. Repeat a few times for a reliable average.

Is it cheaper to drive or fly?

For short and medium trips with two or more people, driving is usually cheaper because the fuel cost is shared. Use the per-person result and compare it with the fare, plus airport transport and baggage fees.

Does driving faster use more gas?

Yes. Aerodynamic drag grows with the square of speed, so most cars become noticeably less efficient above 55–60 mph.

Can I use this for diesel?

Yes. Enter your diesel car's MPG and the diesel price per gallon; the formula is the same.

Last updated November 10, 2026