Is premium gas worth it? What octane really means
If your car doesn't require premium, you're probably paying extra for nothing. Here's how to tell.
The gap between regular and premium at the pump can be substantial on every fill-up. Whether that money buys you anything depends almost entirely on your engine.
What octane measures
Octane isn't a measure of energy or quality. It's a fuel's resistance to knocking, which is when fuel ignites too early in the cylinder. High-compression and turbocharged engines need higher-octane fuel to avoid it.
Check your owner's manual
Look for one of two phrases:
- Premium required. Use premium. Lower octane can reduce performance and, over time, risk engine damage.
- Premium recommended. The car will run safely on regular. You may lose a little power, but usually not enough to recover the extra cost in better mileage.
If your manual just says regular (usually 87 octane), premium gives you no benefit at all.
Top Tier is a different question
Top Tier is a detergent standard, not an octane grade. Many major brands sell Top Tier regular. Cleaner fuel can help keep injectors and valves in good shape, and it doesn't require paying for premium.
Altitude and lower octane
In some high-altitude areas, regular is sold at a lower octane, such as 85. Modern engines generally expect your manual's recommendation, so stick with that unless the manual says otherwise.
Do the numbers
Enter your trip into the calculator at the regular price and the premium price. Seeing the difference for a single road trip makes the choice easy.