How to Calculate Road Trip Gas Cost
The formula is simple: (Total Miles / Vehicle MPG) x Gas Price = Total Fuel Cost. Divide by the number of passengers to split the cost evenly. For round trips, double the one-way distance before calculating.
Popular US Road Trip Fuel Costs
| Route | Distance (one way) | Fuel Cost at 25 MPG | Fuel Cost at 35 MPG |
|---|---|---|---|
| NYC to Washington DC | 225 mi | $31 | $22 |
| LA to Las Vegas | 270 mi | $38 | $27 |
| Chicago to Nashville | 470 mi | $66 | $47 |
| NYC to Miami | 1,280 mi | $179 | $128 |
| LA to San Francisco | 380 mi | $53 | $38 |
| Cross-country (NYC to LA) | 2,790 mi | $390 | $279 |
Estimated at $3.50/gallon average.
Tips to Save Gas on a Road Trip
- Keep speed at 60-65 mph — fuel efficiency drops 7-14% for every 5 mph above 60
- Use cruise control on flat highways — maintains consistent speed and saves 5-7% fuel
- Check tire pressure before departure — underinflated tires waste 3% of fuel
- Remove roof racks if not needed — roof racks add 2-8% drag penalty at highway speeds
- Fill up at cheaper stations en route — use GasBuddy to find prices along your route
- Pack light — every 100 lbs of extra weight costs about 1% MPG
FAQ
Is it cheaper to drive or fly for a road trip?
For 1-2 people, driving is usually cheaper up to about 500 miles. With 3-4 passengers splitting gas, driving is cheaper up to 1,000+ miles. Factor in hotel costs for multi-day drives versus a 4-hour flight.
How many miles can I drive on a full tank?
Multiply your tank size (gallons) by your MPG. A 15-gallon tank at 25 MPG gives 375 miles of range. A 20-gallon tank at 30 MPG gives 600 miles. Plan fill-up stops before your tank hits 1/4 full.
Does driving speed affect gas cost that much?
Yes. Driving at 75 mph instead of 60 mph can increase fuel consumption by 20-25%. On a 500-mile trip, that adds $15-$25 in extra gas and only saves about 45 minutes of drive time.