Calculating How Much Gas You Need for Your Road Trip

U.S. Route 163, Monument Valley
Chaiyun Damkaew / Getty Images

Summertime is road trip time!

Before you get summer's motor running, though, it's worth taking the time to calculate just how much gas you'll use on your road trip and how much money you'll need to spend on this essential.

Fortunately, it's easy to figure out what your gas mileage will likely be. Gas mileage is miles per gallon, or how many miles you can drive on one gallon of gas.

Do you want to know how much your gas is going to cost as well as the whole amount you will spend on gas over the course of a trip? While this is slightly more complicated, it's still easy to understand.

How Much Gas Will You Need?

Let's get started.

Step 1: The next fill up your car, take the time to write down your odometer reading or set your trip meter to zero. To do so, push in the little knob underneath the odometer—read the owner's manual if you have a newer car with a computerized console. Or simply look up your car's model online to find instructions on how to do it.

Step 2: Next, you want to drive until you're close enough to empty that you need to fill up again. Try to leave it as empty as possible to gain a more accurate reading.

Step 3: Head to a gas station. Before you fill your tank with gas, write down the odometer reading.

Step 4: Subtract that number from the first odometer reading you wrote down. That way you'll know how much gas you went through on your trip.

Step 5: Divide that resulting figure by the number of gallons you just purchased to arrive at your miles per gallon. And that's all you need to know.

Step 6: Now, you can figure out how many miles you'll most likely be traveling on your road trip. Once you have that number, you can divide it by the number you calculated in step five. This number now tells you how many gallons of gas you'll use on your road trip.

If you take a quick look online at the average cost of gas across the country, you can multiply this by the number of gallons you expect to use. You now have a rough estimate of how much money you need to budget for gas on this trip.

Tips and Tricks

Now that you've got your gas budget under control, it's time to start figuring out everything else that's going to ensure you have a successful road trip.

Choose your travel companions carefully. You never truly get to know a person until you travel with them, so if you don't know your road trip buddies very well, prepare yourself for some conflict. It's best to have a discussion with everyone else before you leave to get everyone's expectations in check. You don't want to have any arguments along the way because someone's having to do all of the driving because nobody else wants to.

You should also download HERE Maps in advance of your trip. These maps work offline, and you can get offline directions. This is invaluable if you'll be traveling through large parts of the country where you might not have data or cell coverage.

Edited and updated by Lauren Juliff.