Gas trip cost formula
Fuel cost = trip distance / MPG x gas price per gallon
For a 250-mile trip in a 30 MPG vehicle, the estimate is 250 / 30 = 8.33 gallons. At $3.50 per gallon, that trip costs about $29.17 in fuel.
Fuel estimate
Gas trip cost calculator
Estimate how much gasoline a drive will use before you leave. Enter trip distance, your vehicle MPG, and the local gas price to get gallons used, fuel cost, and cost per mile.
What to enter
- Trip distance: one-way or round-trip miles.
- Vehicle MPG: use highway MPG for road trips or combined MPG for mixed driving.
- Gas price: the price per gallon you expect to pay.
- Extras: tolls, parking, ferry fees, or paid road access.
How to get a realistic fuel estimate
Manufacturer MPG and dashboard MPG are useful starting points, but real trips rarely match the sticker number exactly. Highway speed, stop-and-go traffic, wind, elevation, roof racks, cold weather, tire pressure, and extra passengers can all change the final number.
If you are planning a long drive, run two versions: one with your optimistic MPG and one with a lower MPG. The lower estimate gives you a safer fuel budget and helps compare gas cost against an EV trip or a different route.
Related calculators
Gas trip cost FAQ
Should I use city MPG or highway MPG?
Use highway MPG for steady freeway driving, city MPG for stop-and-go routes, and combined MPG when the drive has both.
Does this include tolls and parking?
The fuel formula only covers gasoline. Use the main calculator extras field or the road trip cost page when tolls, parking, or ferry fees matter.