system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: So what exactly is the difference between the different tiers of gasoline (e.g. "Regular"and Premium)?
gpt
The only difference is the octane rating (the number on each grade). The higher the rating, the more the gas/air mixture can be compressed before spontaneously exploding.

Higher-performance cars compress their gas/air mixture more, so they need the gas with the higher rating. If your car doesn't need it, there is no advantage to buying the more expensive gas.