I f you've ever fueled up in Colorado, you might have noticed something unusual about the gas octane ratings at the pump -- specifically, the availability of 85-octane gasoline. This lower octane ...

87 octane gasoline, often called "regular" gas, is one of the most commonly used fuels in the United States. But what gives it that 87 rating is a word you've probably heard a time or two: Ethanol ...

This is a blend of gasoline that blends gas with 15 percent ethanol. 87-octane can have no more than 10 percent ethanol. The difference between 87 and 88 is an additional 5% ethanol.

The regular gasoline most people purchase typically has an octane rating of 87. The rating for mid-grade gas usually ranges from 89 to 90, and for premium , it falls between 91 and 94.

Retailers base their grades of gasoline at the pump based on the octane levels. As EIA explains, the lowest octane level (usually 87) is considered regular, 89-90 is midgrade, and premium has the ...

Some cars require premium high-octane gasoline, others just recommend it, and most cars are fine running regular 87-octane fuel (it might even be lower at high altitudes). If your car normally ...

Most states have the option of choosing 87, 89 or 93-octane. But in a few states, the gas pumps look a little different.

If you've ever fueled up in Colorado, you might have noticed something unusual about the gas octane ratings at the pump – specifically, the availability of 85-octane gasoline.

Most states have the option of choosing 87, 89 or 93-octane. But in a few states, the gas pumps look a little different.

Most states have the option of choosing 87, 89 or 93-octane. But in a few states, the gas pumps look a little different.