General information only, last reviewed October 25, 2026. Full notice and dates to watch at the end of the page. A date on this page has passed. Check the current rule at the source before you rely on it. Dates to watch
Almost every gallon of regular gasoline sold in the US already has ethanol in it, and a few blends carry a lot more. The E numbers on the pump tell you how much. For a fuel seller, knowing what each blend is, and who can use it, is part of stocking the forecourt correctly.
Reading the E numbers
The number is the percentage of ethanol in the gasoline:
- E10 is up to 10% ethanol, the standard fuel at most pumps.
- E15 is more than 10% and up to 15% ethanol.
- E85 (flex fuel) is 51% to 83% ethanol under the ASTM spec, varying by season and region; 85 is the marketing name.
The rest of each blend is gasoline. E85's range shifts because colder months need lower ethanol for cold starts.
Who can use what
Essentially all gasoline vehicles can run E10, which is why it is the base product almost everywhere. E15 is approved for flex-fuel vehicles and for cars, light trucks, and SUVs from model year 2001 and newer. E85 is only for flex-fuel vehicles built for high ethanol content. Matching the blend to the vehicle is the seller's responsibility to label clearly.
Why most gasoline is E10
E10 became the de facto standard for finished motor gasoline in the US, and nearly every engine is approved for it. When a customer buys regular unleaded, it is almost always E10, so for most fuel sellers E10 is the base product. This connects to the broader product and supply picture.
The fuel economy note
Ethanol carries about a third less energy than pure gasoline, so higher-ethanol blends give somewhat fewer miles per gallon. The effect is small for E10 and E15 and larger for E85. It is a clear factor for fleets weighing flex fuel. The same question comes up on the diesel side with renewable diesel and biodiesel.
The jobber side: RINs and blending
Ethanol is where the Renewable Fuel Standard touches a jobber's margin. Each gallon of ethanol carries a RIN, a Renewable Identification Number, and the party that blends the ethanol into gasoline separates that RIN and can sell it or bank it for compliance. Position decides who gets it. Buy pre-blended E10 at the rack and the rack seller keeps the RIN. Buy the ethanol with its RIN attached and splash blend it yourself, into the truck or your own tank, and you are the blender who separates it. That takes EPA registration in advance, both as an ethanol blender and as a RIN owner. RIN values move with policy and the corn market, so run the math on current prices before building a blending position. Every blend you carry is also its own product with its own spec, cost, and tax, which is why FastDragon Fuel Jobber tracks each blend separately.
Common questions
Can E15 be sold year-round?
It depends on the state and the year. Federal volatility rules give E10 a 1 psi summer allowance that E15 does not get, which keeps E15 off retail pumps from June 1 to September 15 in much of the country unless EPA issues an emergency waiver. EPA issued one every summer from 2022 through 2026. Reformulated gasoline areas can sell E15 year-round. At their governors' request, EPA removed the E10 allowance in Illinois, Iowa, Minnesota, Missouri, Nebraska, Wisconsin, and South Dakota (most counties in 2025, the rest in 2026), which opens those states to summer E15. Ohio reversed its request before the change took effect there. No federal law makes E15 year-round nationwide yet, so check the current EPA fuel-waiver status for your state before committing a tank to it.
Does E15 damage engines or void warranties?
EPA approved E15 only for cars, light trucks, and SUVs from model year 2001 forward, plus flex-fuel vehicles. It is not approved for motorcycles, heavy-duty gasoline trucks, boats, lawn equipment, or anything older. Federal rules make it illegal to sell or put E15 into those engines, and running it there can void the warranty. The orange-and-black pump label exists to keep those gallons out of the wrong tanks.
How much worse is fuel economy on E85?
DOE fuel-economy data shows flex-fuel vehicles typically travel 15% to 27% fewer miles per gallon on E85 than on gasoline. E85 usually sells at a discount, so the cost per mile can still come out close to even. The per-gallon price alone overstates the savings.
What is the ethanol blend wall?
If nearly all gasoline is E10, ethanol can only make up about 10% of total gasoline demand. That ceiling is called the blend wall, and it is why ethanol producers push E15 and E85: those blends are the only way to move more ethanol gallons once every tank of regular already carries its 10%.
Is ethanol-free gasoline still available?
Yes. E0, often sold as recreation fuel, survives as a premium niche product for boats, small engines, classic cars, and other equipment that handles ethanol poorly. Stations that carry it usually price it well above regular, and for some rural and marina locations it is a steady traffic draw.
Sources: EPA fuel rules at 40 CFR 1090.80 (E15 definition), 1090.215 (summer RVP and the 1 psi allowance), 1090.230 (where E15 may be used), 1090.115 (ethanol blenders), and 1090.1510 (E15 pump label); EPA's Ohio waiver notice (91 FR 5108), fuel waivers, and April 2024 E15 waiver release; the status of H.R. 1346 in Congress; RIN rules in 40 CFR part 80, subpart M; the FTC Fuel Rating Rule (16 CFR part 306); and DOE data on E85 and flex-fuel mileage.