According to the U.S. Department of Energy:
E10 and E15 are blends of ethanol and gasoline the number after the "E" indicates the percentage of ethanol by volume.
Most of the gasoline sold in the U.S. Contains up to 10% ethanol the amount varies by region and all auto manufacturers approve blends up to E10 in their gasoline vehicles.
As of 2011, EPA began allowing the use of E15 in model year 2001 and newer gasoline vehicles.2 Pumps dispensing E15 must be labeled (see example). The vehicle owner's manual may indicate the manufacturer's maximum recommended ethanol content.
Since ethanol contains about two-thirds as much energy as gasoline, vehicles will typically go 3% to 4% fewer miles per gallon on E10 and 4% to 5% fewer on E15 than on 100% gasoline.
Monday, November 9th, 2015 AT 9:47 AM