Labeling

The labeling of fuels in the U.S. depends on the octane fuel rating. which must be displayed on the labels of all retail gasoline dispensers. Generally, the AKI number (RON+MON)/2 is shown at the pump. Regular grade is usually 87, medium grade 89 and premium between 91 and 93 AKI.

E15 is usually labeled as regular 88, so that users are aware of the different grade.