Regular vs Premium Gas: When Is Premium Worth Paying For?
What octane really means, which cars need premium, which only recommend it, and how much choosing premium costs you each year.
Updated October 8, 2026
📊 U.S. national averages · EIA week of Nov 9, 2026
Premium gasoline (usually 91–93 octane) costs noticeably more than regular (87): the gap between the national averages is often 70 cents to more than a dollar per gallon (about $1.05 in early October 2026). The box above shows today’s national average for premium.
What octane means
Octane measures resistance to “knock” (premature ignition). Engines with high compression or turbocharging may need higher octane. Octane does not mean more energy, cleaner fuel or better mileage in an engine designed for regular.
Required vs recommended
- “Premium required”: use premium. Lower octane can cause knock and the engine may reduce power to protect itself.
- “Premium recommended”: regular is safe; you may lose a little performance.
- Regular specified: premium brings no benefit.
The cost of choosing premium
At 12,000 miles a year and 28 MPG, you buy about 430 gallons. With a $1.00 gap, premium costs around $430 more per year. The FTC and AAA have both found that most drivers using premium in regular-fuel cars gain nothing.
Frequently asked questions
Does premium clean my engine?
Detergent additives depend on the brand; many regular gasolines meet “Top Tier” detergent standards too.