Understanding the Real Difference Between 87 and 89 Octane Gas
Selecting the right fuel at the pump can feel like an unnecessary guessing game, especially when staring at the price differences between the yellow buttons. At U.S. gas stations, 87 octane is classified as regular gasoline, while 89 octane represents mid-grade fuel. The core difference between these two options is not the cleanliness of the fuel or the energy content inside each gallon. Instead, the octane rating measures a fuel's chemical stability and its specific resistance to engine knocking or pinging during combustion.