This Is How Much Gas You Should Keep in Your Tank

Keeping your tank at least one-quarter filled can help prevent damage and extend the life of your car.

Nothing is more annoying when you’re ready to hit the road than realizing you need gas. Between the time it takes to fill up, the cost and the general inconvenience, you might wonder whether you can cruise a little longer without stopping.

A better question is whether there’s actually an ideal amount of gas to keep in your tank. The answer is yes, according to experts. It’s one of many ways you can help extend the life of your vehicle.

How a Gas Tank Works

For starters, understand how your gas tank works. Bill Evans, the manager of J & E Auto Body in Clark, New Jersey who’s worked with cars for more than 30 years, says your tank includes a fuel pump that connects to the motor. The pump heats up as it runs. When it’s submerged in gas, the fuel acts as a coolant to prevent overheating. If you’re running on less than a quarter tank of gas, the pump will overheat and fail sooner than it should.

What Happens When You Drive on Empty

What’s more, driving with the fuel gauge close to empty creates condensation in the walls of your gas tank. That dilutes your fuel and causes rust, according to Richard Reina, a product training director at It leads to other problems, too.

If you’re driving around on empty, the fuel pump is going to start picking up everything on the bottom of the tank,” Evans says. This includes sediment from dirty gas and tank condensation. Not only can that damage your fuel pump and motor, it reduces your gas mileage as well.

As long as you have a quarter tank of gas, your gas mileage is going to stay as optimal as it could,” Evans said. “The filter isn’t getting hot. The motor isn’t working as hard. That all helps on your gas mileage. If you’re keeping a quarter a tank of gas or more in the car, you’ll prolong the life of the fuel system parts.”

So there you have it. Maybe it’s time to break your habit of using the last drops of fuel to roll to the gas station.

Reader's Digest
Originally Published on Reader's Digest

Erin Kayata
Erin Kayata joined Reader’s Digest as an assistant staff writer in March 2019, coming from the Stamford Advocate where she covered education. Prior to this, she was part of a two-year Hearst fellowship program where she covered crime and education in suburban Connecticut. She graduated from Emerson College and spent part of her undergraduate career writing for the Boston Globe. When she’s not writing articles about useful facts and pop culture, you can find Erin enjoying the local theater scene and working toward her goal of reading 50 books a year.