How much gas will you use on your road trip?

Will the cost of gas bleed your travel budget dry?
Will the cost of gas bleed your travel budget dry?

Americans love road trips. In 2011, AAA estimated that 32.8 million Americans drove a distance of 50 miles (80.5 kilometers) or greater during the Fourth of July weekend [source: AAA]. While that's an impressive figure, it's nearly a million less than the number of travelers that hit the road in 2010. Why? The price of gasoline. The national average for a gallon of regular unleaded jumped nearly a dollar a gallon from the previous year, from about $2.70 to $3.60 [source: AAA]. The high cost of fuel doesn't have to stall your plans, though. It's easy to minimize the amount of gasoline you'll use on your trip and calculate about how much it will cost you, ensuring your drive is both affordable and carefree.

There are several steps you can take to reduce your gasoline before you even pull out of the driveway. When planning a long road trip, it's a good idea to have a mechanic change the oil and fix any problems that may exist. Repairing a car that's out of tune can improve fuel efficiency by an average of 4 percent, while fixing a faulty oxygen sensor can increase gas mileage by a whopping 40 percent. You should also check to ensure that your tires are properly inflated. For each pound per square inch that your tires are underinflated, your fuel economy is reduced by 0.3 percent [source: EPA]. Finally, pack light. Every 100 pounds added to a car's weight results in a 2 percent reduction in gas mileage, and tying luggage to the top can lead to a decrease of up to 21 percent [source: EPA, Valdes-Dapena].



Once you're on the road, there are more ways to reduce how much gas goes in the tank. Consider taking scenic back roads with lower speed limits; fuel efficiency is dramatically reduced at speeds greater than 60 miles per hour (96.5 kilometers per hour) [source: EPA]. On flatter stretches of road, use the cruise control. Allowing the car to decide when to apply acceleration instead of doing it yourself can increase gas mileage by 10 to 15 percent [source: Valdes-Dapena]. Timing your route properly can also save fuel. Stay away from big cities during rush hour when stop-and-go traffic can bring your progress to a standstill and reduce your gas tank to vapors. Consider investing in a GPS unit or mobile phone app like Google Maps, which can actually display traffic congestion in real time, allowing you to plan a detour far in advance of any problems.

While these tips can reduce your gasoline usage, they won't completely eliminate it, so it's still nice to know about how much fuel you will use on your road trip. Read on to learn how to calculate what your drive will cost.

Calculating the Cost of Gas for a Road Trip

Fuel costs for long road trips can be startlingly high, especially if you don't know what to expect ahead of time. Luckily, calculating the cost of gas for your road trip is a matter of simple arithmetic, and there are even several Web sites that will do the math for you.

Before you can determine the cost of gas for your road trip, you need to figure out your vehicle's gas mileage. Typically, this number is listed in your owner's manual or can be found on the Internet. If not, you can calculate it yourself by first filling up the tank and resetting the trip odometer. Once you've used at least half of the gasoline in the tank, fill the tank again and note how much fuel you put in the car, as well as the mileage on the odometer. Then divide the number of miles by the gallons of fuel to get your vehicle's miles per gallon (MPG) rating. For example, if you traveled 250 miles on 10 gallons of gasoline, your car's MPG rating is 25.



Once you know your car's MPG, you can calculate the amount of fuel you'll need on your road trip. First, find out how many miles you plan to drive by entering your starting and ending points into an online maps program like MapQuest or Google Maps. Then divide this mileage figure by your car's MPG rating to find out how many gallons of fuel you'll need on your trip. For instance, if you plan to drive 500 miles in a car that gets 25 MPG, you'll need about 20 gallons of gasoline. To find out your total fuel cost, visit the American Automobile Association's (AAA) Daily Fuel Gauge Report to determine the average gas prices in the area you'll be driving. Multiply the number of gallons you need times the average gas price to get your total fuel cost. For example, if gas is about $3.50 a gallon in your area and you need 20 gallons to drive your trip distance, you'll pay $75 for gasoline.

Several online calculators make this figuring even easier. Typical of these Web sites is AAA's Fuel Cost Calculator, which allows you to select your departure and arrival cities, as well as the make and model of your car. It then uses the current average price of gasoline in the areas in which you plan to drive to calculate your total fuel cost. offers a similar service, but its calculator can actually schedule your fuel stops based on the lowest gas prices along your route. With these tools, you'll never be surprised when it comes time to fuel up.

For links to fuel cost calculators and other great information, click over to the next page.

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More Great Links


  • American Automobile Association. "AAA Projects a 2.5 Percent Decrease in Independence Day Travel as Americans Fly More and Drive Less." June 22, 2011. (July 10, 2011)
  • American Automobile Association. "Daily Fuel Gauge Report." July 10, 2011. (July 10, 2011)
  • Clark, Jayne. "Don't Let High Gas Prices Stall Your Plans." USA Today Travel. May 8, 2011. (June 10, 2011)
  • Environmental Protection Agency. "Driving More Efficiently." July 7, 2011. (July 10, 2011)
  • Environmental Protection Agency. "Keeping Your Car in Shape." July 7, 2011 (July 10, 2011)
  • Duvauchelle, Joshua. "How to Calculate Gas Mileage for a Trip." USA Today Travel. 2011. (July 10, 2011)
  • Grant, Kelli B. "Finding Cheap Gas Amid Road-Trip Traffic." June 30, 2011. (July 10, 2011)
  • Higgins, Michelle. "13 Ways to Save on Gas This Summer." The New York Times. May 11, 2011. (July 10, 2011)
  • Roberts, Amy. "Save Gas on Your Next Road Trip." Good Housekeeping. June 29, 2011. (July 10, 2011)
  • Valdes-Dapena, Peter. "Gas Saving Road Trip Tips." CNN Money. April 22, 2008. (July 10, 2011)