E85 Flex Fuel
A high-octane gasoline–ethanol blend (51–83% ethanol) for flex-fuel vehicles, with meaningful lifecycle GHG benefits.
What it is
E85 is a blend of ethanol (typically 51–83% by volume, depending on season and region) and gasoline. It carries a high octane rating (~105 R+M/2), which is why the performance and racing community has historically used it.
Will my vehicle run it?
Flex-fuel vehicles (FFVs) only — running E85 in a non-FFV gas engine causes damage.
- Check your owner's manual or door-jamb sticker for "FFV" / "Flex Fuel" designation.
- Common FFVs: Ford F-150 FFV, Chevy Silverado FFV, many GM, Ford, and Stellantis models 2002+.
- Some performance applications use E85 with engine modifications; that is its own rabbit hole.
Environmental impact vs. regular gasoline
- ~40% reduction in lifecycle CO2-equivalent emissions vs. regular gasoline.
- Energy density is ~74% of regular gasoline; expect roughly 26% fewer miles per gallon, which the per-mile reduction calculation already accounts for.
Sources: CARB Low Carbon Fuel Standard pathway data; EPA Renewable Fuel Standard lifecycle analysis; NREL / Argonne GREET model.
Trade-offs and caveats
- Lower energy density means MPG drops ~25–30%; the per-mile reduction is smaller than the per-gallon reduction.
- GHG reduction varies dramatically by feedstock — corn-starch ethanol is at the low end, cellulosic ethanol at the high end.
- Higher octane is a direct benefit for forced-induction or high-compression engines.
- Cold-weather start can be marginal at very low temperatures; many regions sell a winter blend with lower ethanol percent.
Where to find it
Densest in the Midwest (corn ethanol producing states), with growing presence in Texas, California, and the Southeast.
Browse E85 Flex Fuel stations on the map or jump to a state-level directory: California, Oregon, Washington, Texas, or all US states.
FAQ
What is E85 Flex Fuel?
E85 is a blend of ethanol (typically 51–83% by volume, depending on season and region) and gasoline. It carries a high octane rating (~105 R+M/2), which is why the performance and racing community has historically used it.
Will my vehicle run E85 Flex Fuel?
Flex-fuel vehicles (FFVs) only — running E85 in a non-FFV gas engine causes damage. Check your owner's manual or door-jamb sticker for "FFV" / "Flex Fuel" designation. Common FFVs: Ford F-150 FFV, Chevy Silverado FFV, many GM, Ford, and Stellantis models 2002+. Some performance applications use E85 with engine modifications; that is its own rabbit hole.
What is the environmental impact of E85 Flex Fuel?
Environmental impact vs. regular gasoline ~40% reduction in lifecycle CO2-equivalent emissions vs. regular gasoline. Energy density is ~74% of regular gasoline; expect roughly 26% fewer miles per gallon, which the per-mile reduction calculation already accounts for.
What are the trade-offs of using E85 Flex Fuel?
Lower energy density means MPG drops ~25–30%; the per-mile reduction is smaller than the per-gallon reduction. GHG reduction varies dramatically by feedstock — corn-starch ethanol is at the low end, cellulosic ethanol at the high end. Higher octane is a direct benefit for forced-induction or high-compression engines. Cold-weather start can be marginal at very low temperatures; many regions sell a winter blend with lower ethanol percent.
Where can I find E85 Flex Fuel stations?
Densest in the Midwest (corn ethanol producing states), with growing presence in Texas, California, and the Southeast. OpenFuel maps every known E85 Flex Fuel station in the US, with crowdsourced prices when available.