Gas shortage: Is it OK to put premium unleaded in a regular unleaded car?

On average, the price difference between regular and premium gasoline is approximately 20 to 25%, or 50 cents per gallon

As gas shortages continue across the East Coast due to panic buying, some drivers are getting desperate, looking for fuel anywhere they can.

While some vehicle owners are getting warned against hoarding gas in plastic bags, others are considering putting premium unleaded gasoline into their vehicles which are made for regular unleaded gasoline. Typically, "regular" gas is 87 octane, while anything over 91 octane is considered "premium" gasoline. 


A spokesperson with the American Automobile Association told FOX Business that it is safe to use premium fuel in your vehicle even if it takes regular. 

"However the reverse is not true – if you have a vehicle that requires premium – you should never use regular," the spokesperson warned.

According to, the official U.S. government source for fuel economy information, using regular gas in older vehicles made for premium gasoline can result in the engine making an audible knocking or pinging sound. In some cases, it can also void your warranty.

However, the electronic computer unit (ECU) in newer vehicles can simply adjust engine timing and performance to work with the lower-octane fuel, though engine power and fuel economy can still suffer if regular gas is used in a premium tank for an extended period of time.  


While it is safe to put the higher-priced premium gas into your regular gas tank, previous research by AAA has shown that any potential benefit may not outweigh the cost. A 2016 AAA study found that drivers waste $2.1 billion annually putting premium gas into vehicles that do not require it. 

While the 2016 study initially found no improvement in horsepower, fuel economy, or emissions when putting premium gasoline into a car that takes regular, researchers later determined in 2017 that some drivers may see increased fuel economy and performance under certain driving conditions when using the higher-octane gasoline.

In partnership with the Automobile Club of Southern California’s Automotive Research Center, AAA tested a variety of vehicles that recommend, but do not require, the use of premium (91 octane or higher) gasoline. A combination of laboratory and on-road tests were performed to simulate extreme driving scenarios such as towing, hauling cargo and aggressive acceleration.

When using premium fuel in vehicles under these conditions, researchers found that fuel economy for test vehicles averaged a 2.7% improvement. Individual vehicle test result averages ranged from 1% decrease in the 2016 Audi A3 to a 7.1% improvement in the 2016 Cadillac Escalade. Meanwhile, horsepower averaged an increase of 1.4% improvement. Individual vehicle test result averages ranged from a 0.3% decrease in the 2016 Jeep Renegade to a 3.2% improvement in the 2017 Ford Mustang.

"There’s no question that higher-octane premium fuel has the potential to boost a vehicle’s fuel economy and performance, however, engines have to be calibrated to require that fuel to see the full benefit," AAA’s managing director of Automotive Engineering and Repair John Nielsen said in a statement. "Based on AAA’s testing, vehicles that only recommend premium gasoline can’t take full advantage of higher octane fuel and, as a result, the benefit that comes from upgrading to premium gasoline may not offset its high cost."


According to national averages, the price difference between regular and premium gasoline is approximately 20 to 25%, or 50 cents per gallon.

On Wednesday, the national average gas price topped $3 per gallon, the most expensive level since 2014, following the cyberattack on the Colonial Pipeline. According to AAA, the current national average as of Thursday is $3.02 per gallon. 

The Colonial Pipeline has since been restarted, and the company said in an update on Thursday that each market it services should expect to receive fuel later today.