List of U.S. states by standard octane ratings

Most U.S. states do not mandate specific gasoline octane ratings. In the United States and Canada, octane is measured using the Anti-Knock Index (AKI), commonly shown as "(R+M)/2". All states require pumps to display the correct octane rating, and most conduct regular compliance testing. Since 1984, 87 AKI has been the recommended minimum for fuel-injected vehicles. Older carbureted vehicles that required 87 AKI at sea level could use 85 AKI at higher elevations, so 85 octane was widely sold in the Rocky Mountain states and other high-elevation areas. However, as carbureted vehicles have disappeared, the availability of lower-octane fuels has declined, and they have already been phased out in states such as Alaska, Maine, and North Dakota.

State octane ratings

Map of the US by premium gas minimum

The octane ratings below are the lowest allowed by law for unleaded fuel and may or may not reflect the actual levels offered for sale at most gas stations. Ethanol's effect on octane is not considered—these are ratings that are seen at the pump.

State	Regular	Mid-grade	Premium	Notes
Alabama	87	89	93
Alaska	87	88.5	90
Arizona	87	89	91
Arkansas	87	89	91	93 octane premium is sold at select stations
California	87	89	91
Colorado	85	87	91
Connecticut	87	89	93	86 octane may be sold if labeled as economy[1]
Delaware	87	89	93
Florida[2]	87	89	93	91 octane premium is sold at select stations alongside 93 octane.
Georgia[3]	87	89	93
Hawaii	87	89	92
Idaho	85/87	87/89	91	In eastern Idaho’s higher elevations, octane grades are 85/87/91, while in western Idaho they are 87/89/91.
Illinois[4]	87	89	91	93 octane premium is sold at select stations
Indiana	87	89	93
Iowa	87	89	91	Select stations sell "Super Unleaded" 87 with 10% ethanol, ethanol-free 87, and 93 octane premium.
Kansas	87	89	91	93 octane premium is sold at select stations
Kentucky[5]	87	89	93
Louisiana	87	89	93
Maine	87	89	91/93	Premium is 91 without ethanol, or 93 when blended with 10% or more ethanol
Maryland	87	89	93
Massachusetts	87	89	93
Michigan	87	89	93	85 and 86 octane may be sold if labeled as subregular[6]
Minnesota	87	89	91	110 octane premium is sold at select stations
Mississippi	87	89	93
Missouri	87	89	91/93	Premium is 91 without ethanol, or 93 when blended with 10% or more ethanol
Montana[7]	85.5	88	91
Nebraska	87	89	91
Nevada	87	89	91	High-elevation areas in eastern Nevada use 85/87/91 octane ratings.
New Hampshire	87	89	93
New Jersey	87	89	93
New Mexico	86	88	91
New York[8]	87	89	91/93	93 octane premium is sold at select stations
North Carolina	87	89	91/93	91 octane is commonly sold as "premium" in the western, mountainous part of the state.
North Dakota[9]	87	89	92
Ohio	87	89	93
Oklahoma	87	89	91
Oregon	87	89	92
Pennsylvania	87	89	93
Rhode Island	87	89	93
South Carolina	87	89	93	Lower-octane gasoline may be sold if labeled as "sub-standard" or "sub-regular".[10]
South Dakota	85/87	87/89	91	In designated high-elevation counties, 85 (with 87 as mid-grade) may be sold, with a warning label at the pump.[11][12]
Tennessee	87	89	93
Texas	87	89	93	El Paso, Lubbock, and Amarillo areas use 86/88/91 octane ratings.
Utah	85	88	91
Vermont	87	89	93
Virginia	87	89	93
Washington	87	89	92
West Virginia	87	89	93
Wisconsin	87	89	91	93 octane premium is sold at select stations
Wyoming	85	88	91