Fuel Cost Calculator
Planning a road trip means knowing what you will spend on gas before you leave. Fuel is typically one of the largest variable costs of any long-distance drive, and even a small difference in fuel efficiency or gas price can add up significantly over hundreds of miles. The calculation is straightforward: divide your trip distance by your vehicle's fuel efficiency in miles per gallon to find the gallons required, then multiply by the current price per gallon. Knowing your cost per mile is also useful for comparing driving to other transport options or for claiming mileage reimbursements. The EPA publishes official fuel economy ratings for every model year vehicle at fueleconomy.gov, and the U.S. Energy Information Administration publishes weekly regional gas prices at eia.gov. For the most accurate estimate, use your actual observed mpg from recent fill-ups rather than the EPA rating, since real-world results vary with speed, load, terrain, and driving style. Enter your trip distance, fuel efficiency, and current gas price below to get your estimated fuel cost, gallons needed, and cost per mile.
Total fuel cost: -- | Gallons needed: --
Typical vehicle fuel economy
| Vehicle type | Typical highway mpg |
|---|---|
| Compact car | 35-42 mpg |
| Mid-size sedan | 30-36 mpg |
| Hybrid sedan | 45-55 mpg |
| SUV (small) | 27-34 mpg |
| SUV (large) | 22-28 mpg |
| Pickup truck | 18-25 mpg |
| Minivan | 24-30 mpg |
Source: U.S. Department of Energy, fueleconomy.gov. Actual fuel economy varies by model year, speed, load, and driving conditions.
Tips to reduce fuel costs on road trips
Maintain steady highway speeds between 55-65 mph; fuel economy drops noticeably above 65 mph. Keep tires inflated to the recommended pressure, avoid excess cargo weight, and use cruise control where safe to maintain consistent speed. Reducing air conditioner use at moderate temperatures can also improve efficiency by 5-25%.
Fuel cost: frequently asked questions
How is road trip fuel cost calculated?
Fuel cost is calculated as: (trip distance in miles / fuel efficiency in mpg) * price per gallon. This gives the gallons consumed multiplied by the cost per gallon. For example, a 300-mile trip at 30 mpg with gas at $3.50/gallon uses 10 gallons and costs $35.00.
What is a good mpg for a road trip?
Highway mpg is typically higher than city mpg. Compact cars often achieve 35-40 mpg on the highway. Mid-size sedans average around 30-35 mpg. SUVs typically achieve 25-30 mpg. Trucks and large SUVs may average 18-24 mpg. Hybrid vehicles can exceed 45 mpg on the highway.
Where can I find current gas prices?
The U.S. Energy Information Administration (EIA) publishes weekly retail gasoline prices by region at eia.gov. GasBuddy and AAA also track real-time prices, but check the official EIA data for authoritative regional averages.
How do I convert L/100km to mpg?
To convert from L/100km to mpg (US), use the formula: mpg = 235.214 / L100km. For example, 7 L/100km equals approximately 33.6 mpg.
Does this calculator account for city vs. highway driving?
The calculator uses the single mpg figure you enter. For mixed driving, use your vehicle's combined mpg rating, which typically falls between the city and highway estimates shown on the EPA fuel economy label.
References
- U.S. Department of Energy. "Fuel Economy Guide." fueleconomy.gov
- U.S. Energy Information Administration. "Weekly Retail Gasoline and Diesel Prices." eia.gov
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.