It appears that pressing our luck and the gas pedal at the same time has become our national pastime — especially with fuel prices recently hitting all-time highs. We’re talking, of course, about the practice of driving on an empty tank of gas.
Is it safe to do it? Does it harm your car? How far is too far? All good questions. Let’s tackle the last question first.
How Far Can My Car Go on Empty?
When the fuel warning light comes on (or the needle points to empty if you’re driving a classic), you haven’t run out of gas, but it is definitely time to take action.
In most vehicles, it means you’ve got about 10 - 15% of your fuel remaining, which translates to approximately 30 - 50 driving miles to find a gas station. In most scenarios, that’s ample time to react.
Driving on Empty Distance: The Math
If those averages — which can certainly vary — are too vague for your comfort level, and you don’t mind a little math, there is a way to get more precise numbers for your specific vehicle.
In preparation for this exercise, you’ll need two pieces of vehicle information:
Vehicle Miles Per Gallon (MPG)
Vehicle Fuel Tank Capacity (FTC)
You probably know what kind of mileage your vehicle gets, but you may not know your fuel tank capacity. For that, you can go to the “specifications” section of your owner’s manual. It will be expressed in gallons as shown here:
(2022 Honda Accord)
Okay. Armed with those numbers, it’s number-crunching time!
The Three-Step Solution
The process for determining driving distance on an empty tank of gas involves three easy calculations that must be worked in order. For the purposes of this example, we’ll use the information we’ve pulled from the 2022 Honda Accord owner’s manual.
Step 1: Determine Remaining Gas
The first thing you want to know is how much gas is left in the tank.
Here’s the formula for calculating Remaining Gas (RG):
FTC x 10% = RG
With the Accord’s FTC number plugged in:
14.8 x .10 = 1.5
This tells us that we have a gallon and a half of gas left when the Accord hits “empty.”
Step 2: Determine Remaining Miles
The next thing you want to do is convert the Remaining Gas into Remaining Miles (RM). This will tell us how far we can travel with the fuel we have in the Accord.
Here’s the formula for calculating Remaining Miles:
MPG x RG = RM
With the Accord’s mileage numbers plugged in:
33 x 1.5 = 49.5 Remaining Miles
We need to find a gas station within 49.5 miles from our present location.
Step 3: Compare RM to Gas Station Distance (GSD)
When faced with this scenario, If you have internet access, you should do a search for the nearest gas station. With that, you can subtract the distance of that gas station (GSD) from your Remaining Miles.
Here’s the formula for that:
RM - GSD = ?
Continuing with our Accord example, if the closest gas station were 40 miles away when our fuel tank registered “empty,” the formula shows we should be able to make it to the gas station with 9.5 miles to spare:
49.5 - 40 = 9.5
Calculating Your Comfort Level
So, that’s the math behind the calculations for driving on empty. If the final number is positive, you can probably make it. If not, you need to seek some form of roadside assistance.
How close you want to cut it if you find yourself in this position, is something that you’ll have to calculate for yourself!
Feel free to print out your very own copy of our “Running on Empty” formula. It’ll fit nicely into your glove box… you know, that compartment beneath the dashboard on the passenger side where you never keep your gloves!
Should You Drive on an Empty Tank?
Put down your calculator, because it’s time to consider the safety aspects of driving on an empty tank of gas.
Unless you’re an adrenaline junkie with discretionary money set aside for funding avoidable car repairs, we strongly advise you to avoid driving on an empty tank.
Here are some potential issues:
The Fuel Pump
Most vehicles with an electric fuel pump have it submerged at the bottom of the gas tank to keep it from overheating. If gas levels get too low, the pump becomes exposed and the needed cooling does not happen. That can lead to pump failure.
Additionally, the bottom of the gas tank accumulates dirt and contaminants over time, which will get stirred up and sucked into the fuel pump when overall gas levels are low. This, again can result in mechanical problems and/or complete malfunction — particularly for those who make a habit of running on empty.
Repair or replacement costs for fuel pumps can range from $220 to just over $1,000, depending on the make and model of the vehicle.
The Catalytic Converter
Like the fuel pump, a catalytic converter is built to take a certain amount of of punishment, so running low or completely out of gas one time probably won’t do your vehicle in, but repeated behavior like that will eventually do it in.
Replacement costs of a catalytic converter: Up to $2,475 dollars, which could come close to totalling the value of some older vehicles.
The Engine
Even the engine will not escape the havoc that running on empty will bring. When fuel levels are low, the fuel may go into one engine cylinder but not another, causing a misfire and damaging the engine.
More commonly, however, is the damage caused when a vehicle low on fuel is run with a wide-open throttle. The fuel pump can’t provide enough fuel to match the onboard computer’s air-fuel ratio which causes the engine to run much too hot. Again, not good for the engine and damage may result.
Repair/replacement costs vary greatly, but, believe us, it won’t be cheap.
Your Safety
Enough about the vehicle. Your safety is first and foremost, right? Getting stranded is never convenient and can be very dangerous, depending on the time of day (or night) and location.
High-speed traffic, lack of shoulders on the road, poor lighting, depending on the kindnesses of strangers… That all makes for a great Halloween Horror movie plot, but we don’t recommend it in real life. Your life.
So, do yourself a favor and plan ahead whenever you get into the car by:
Always keeping your gas tank at least a quarter of the way full
Implement gas-saving practices so that the gas you do buy goes further
Keeping an emergency road kit in your car in case you do run out of gas or get stranded for other reasons
Know your route
Keep your cell phone charged
Another way to learn some safety techniques that may also save you money is by signing up for a defensive driving course at Aceable.com. You can learn these helpful techniques from certified instructors all from your own home.
Updated 9/8/22