Frequently Asked Questions

How much ethanol is in gasoline and how does it affect fuel economy?

In 2013, about 135 billion gallons of motor gasoline (3.2 billion barrels) were consumed in the United States, which contained about 13 billion gallons of ethanol. Ethanol accounted for about 10% of the total volume of finished motor gasoline consumed.

Most of the gasoline now sold contains some ethanol, but the exact amount varies by region. In general, the ethanol content does not exceed 10% by volume. Gasoline with 10% ethanol content is referred to as E10 and with 15% ethanol as E15. E85 means there is 85% ethanol and 15% gasoline. Most of the gasoline with more than 10% ethanol is sold in the Midwest.

All gasoline vehicles can use E10. Currently only light-duty vehicles with a model year 2001 or greater can use E15. Only "flex-fuel" vehicles can use gasoline with an ethanol content greater than E15.

The energy content of ethanol is about 33% less than "pure" gasoline, although this varies depending on the amount of denaturant that is added to the ethanol. Thus, vehicle fuel economy may decrease by up to 3.3% when using E10.

Learn more:

E85 fueling station availability is increasing

EPA issues proposed rule for the 2014 Renewable Fuel Standard

Biofuels markets face blending constraints and other challenges

Ethanol Blend Wall: Are We There Yet?

Gasoline with higher ethanol content getting closer to U.S. drivers' fuel tanks

Last updated: May 1, 2014

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