How to estimate the gas cost of a trip
- Get the distance from your map app. Tick Round trip if you are driving back the same way.
- Enter your car's MPG. Use your highway figure for long trips; it is usually 15% to 30% better than city driving.
- Enter the gas price along your route. Prices vary a lot between states.
- Add the number of people sharing the cost to see each person's share.
Fuel cost formula
Fuel cost = gallons × price per gallon
Cost per person = fuel cost ÷ people
Worked example
A 600 mile drive in a car that gets 30 mpg needs 600 ÷ 30 = 20 gallons. At $3.25 a gallon that is $65.00 one way, or $130.00 for the round trip. Split between three friends, each pays about $43.33.
How MPG changes the cost of a 1,000 mile trip
| Fuel economy | Gallons | Cost at $3.25/gal |
|---|---|---|
| 18 mpg (large SUV, pickup) | 55.6 | $180.56 |
| 25 mpg (midsize SUV) | 40.0 | $130.00 |
| 32 mpg (sedan) | 31.3 | $101.56 |
| 50 mpg (hybrid) | 20.0 | $65.00 |
Ways to spend less on gas on a road trip
- Drive at 60 to 65 mph instead of 75 mph. Air drag rises fast with speed.
- Check tire pressure before you leave, cold, using the number on the door jamb.
- Pack light and skip the roof box if you can.
- Fill up before crossing into an expensive state and use a gas price app to find cheaper stations near the highway.
Driving electric? Use the EV charging cost calculator instead.
Frequently asked questions
How do I calculate gas cost for a trip?
Divide the distance by your car's miles per gallon to get gallons, then multiply by the price per gallon. A 600 mile trip at 30 mpg and $3.25 a gallon costs $65.
How much gas does a 1,000 mile trip take?
It depends on your fuel economy. At 25 mpg you need 40 gallons; at 32 mpg about 31 gallons; at 50 mpg only 20 gallons.
Should I use city or highway MPG for a road trip?
Use highway MPG for long interstate drives. If the trip includes a lot of city traffic or mountains, use a figure between the two or your measured average.
How do you split gas money fairly?
Calculate the total fuel cost for the trip and divide it by the number of people riding. Some groups exclude the driver or add a share for wear and tear on the car.
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Last updated October 2026.