List of U.S. states by standard octane ratings

In the United States and Canada, octane ratings are in AKI, commonly shown as "(R+M)/2".

Older cars with carburetors could operate with lower octane fuel at higher elevations.

Regardless of legality fuel with an octane rating of less than 82 is generally not offered for sale in most states.

However 85 and 86 octane gasoline can still commonly be found in several Rocky Mountain states but availability is declining due to fewer cars with carburetors being still on the road and they are already gone in many states that previously sold it like Alaska, Maine and North Dakota.

The octane ratings below are the lowest allowed by law and may or may not reflect the actual levels offered for sale at most gas stations.