How Long Can You Drive on Empty?

If the needle on your gas gauge is dropping below E, or the low fuel light has come on, you might have a few questions. Where’s the next gas station? What if I get stuck? Didn't this happen in a "Seinfeld" episode? And how long can I drive on empty?

The cheeky answer to that last one is: Until you run out of gas. So, perhaps the question should really be: How long can you drive on empty without running out of gas? That gets a little more complicated.

Every fuel tank is different

Every vehicle has a different amount of "fuel reserve." This is the amount of fuel left in the tank when the low fuel light comes on. The exact amount of remaining fuel will vary by manufacturer and tank size. It can range from less than a gallon in a small car to as much as four gallons in some large pickups and SUVs. Check your owner’s manual to find yours.

That low fuel light is intended to be a reminder not to drive much farther without refilling. Some vehicles also have a "miles to empty" reading on the display. But this isn’t always trustworthy, because it’s based on an average of your previous driving data.

Fuel gauges aren’t very accurate

The way your gas gauge tracks your fuel usage is more about psychology than accurate readings. Studies have shown that drivers like the gauge to remain at the full mark for a while after a fill-up, to help them believe that they're getting good fuel economy, right after spending a lot on a tank of gas. This is why the needle stays at the full mark until you have used the first two or three gallons.

These same studies have also demonstrated that consumers want to have some fuel remaining in their tanks after the needle reaches the empty mark. Carmakers have complied on both points, which means the gauge is more of an estimate than an exact tool.

Your driving style matters

How much time you have once the gauge hits empty depends in part on your driving style. Some drivers are very gentle on the gas, and others like to accelerate quickly from light to light. Some cruise at the speed limit on the highway, and others like to do 15 MPH over.

In the same compact car with the same two-gallon reserve when the low fuel light comes on, the gentle driver might be able to go 60 miles on the highway, while the lead-footed cruiser might last just 45.

Other factors play a part

In addition to your driving style, there are other elements that can affect your fuel economy. Consider these things when estimating how far you think you can get:

• Winds and slippery surfaces reduce MPG
• Lack of regular maintenance cuts MPG
• A heavy passenger or cargo load will hamper fuel economy
• Underinflated tires will limit your range
• Hilly areas and winding roads reduce MPG

Downsides to running out of gas

The good news is you have a little time to fill up once your gauge reads empty. But waiting too long and running out of gas is a very bad idea.

Your car could stall out: If you run out of gas while cruising on a busy highway, you could be struck by the car driving behind you, or you might get hit while you try to get to the shoulder. Or you could be stranded in an isolated area, or in bad weather. Risking your life is simply not worth it.

Your car could be damaged: The fuel pump is responsible for sending gas to the engine. When you run out of gas, this deprives the pump of the fuel it needs to operate properly. This is comparable to running your engine without oil or coolant. The result can be overheating of the fuel pump, which can stress and ultimately damage the pump, requiring an expensive replacement.

If you must drive with a low tank

It’s not something you should make a habit of, but many drivers will find themselves in a low-fuel situation at some point. With that in mind, here are some strategies for maximizing your fuel:

• Keep your tires properly inflated
• Close all the windows for less aerodynamic drag
• Turn off the air conditioner, stereo and all other accessories, including phone chargers
• Accelerate and brake gently, as much as possible
• Try to maintain a steady speed of around 40 MPH, if conditions permit
• Stop and refuel at the first gas station you find, no matter the price