E85 gasoline is not as fuel-efficient as regular unleaded gasoline. According to the U.S. Department of Energy, vehicles that run on E85 gasoline get 15 to 30 percent fewer miles per gallon than vehicles that run on regular gasoline.
E85 gasoline is only safe to use in vehicles designated for Flex Fuel. E85 gasoline contains up to 83 percent ethanol, but only about two-thirds as much energy as gasoline. The exact amount of ethanol varies depending on the season, with summer blends having the highest ethanol content. Although E85 gasoline is typically less expensive on a cost-per-gallon basis, it usually is slightly more expensive when comparing the cost-per-mile to vehicles running gasoline. E85 gasoline is widely available at service stations across the United States.