Frequently Asked Questions

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

In 2012, about 134 billion gallons of gasoline (3.19 billion barrels) were consumed in the United States, which contained about 13 billion gallons of ethanol, accounting for 10% of the volume of gasoline consumed.

Most of the gasoline now sold has some ethanol in it, but the exact amount varies by region. In general, ethanol will not exceed 10% by volume. Gasoline with 10% ethanol content by volume is known as E10, and with 15% ethanol is known as E15. E85 is 85% ethanol and 15% gasoline.

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 mileage may decrease by up to 3.3% when using E10.

All gasoline vehicles can use E10, but currently you need a light-duty vehicle with a model year of 2001 or greater to use E15, and a "flex-fuel" vehicle to use gasoline with an ethanol content greater than E15. Most of the gasoline with more than 10% ethanol is sold in the Midwest.

Learn more:

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: April 12, 2013

Other FAQs about Gasoline