E15 and E85 gas: what they are and which cars can use them
E15 gas is gasoline with up to 15% ethanol. EPA allows it in cars, SUVs, and light trucks from model year 2001 and newer and in flex-fuel vehicles, but not in motorcycles, boats, small engines, or older cars. E85 holds 51% to 83% ethanol and is only for flex-fuel vehicles, which get roughly 15% to 27% fewer miles per gallon on it. Before you switch, check what your owner’s manual allows: some newer cars still list E10 as the limit.
On this page (8 sections)
The short answer
| Fuel | Ethanol | Who can use it | MPG vs gas with no ethanol |
|---|---|---|---|
| E10 (most U.S. gas) | Up to 10% | Any gasoline vehicle | About 3–4% lower |
| E15 | Up to 15% | Model year 2001 and newer cars, light trucks, and SUVs, and flex-fuel vehicles (EPA); your manual may be stricter | About 4–5% lower |
| E85 (flex fuel) | 51–83%, by region and season | Flex-fuel vehicles only | About 15–27% lower |
MPG figures: fueleconomy.gov. Vehicle rules: U.S. Department of Energy, Alternative Fuels Data Center. Checked November 12, 2026.
Can my car use E15?
Under EPA rules, E15 may be used in:
- Cars, light-duty trucks, and medium-duty passenger vehicles from model year 2001 and newer
- All flex-fuel vehicles
It is not allowed in motorcycles, vehicles with heavy-duty engines (like school buses and delivery trucks), boats, snowmobiles, off-road vehicles, lawn mowers, chain saws and other gas equipment, or cars older than model year 2001. Those stay with E10.
Your owner’s manual still matters. EPA’s approval is about emissions rules. The carmaker’s manual says what the engine was designed for. Mazda’s 2022 MX-5 manual, for example, allows fuel with no more than 10% ethanol and says damage from higher blends may not be covered by the warranty. Check the fuel section of your manual or the label inside the fuel door. If it says E10 or “up to 10% ethanol,” stay with E10.
E15 in summer: the 2026 status
Federal rules on gasoline evaporation (vapor pressure) limit E15 sales in much of the country during the summer ozone season, June 1 to September 15. Outside that season, E15 can be sold nationwide. In recent years EPA has used temporary emergency waivers to allow summer E15 sales:
- 2026: EPA issued a nationwide emergency fuel waiver on March 25, 2026, allowing E15 sales starting May 1, 2026. Each waiver can last 20 days at most under the Clean Air Act, so EPA said it would renew them while the fuel supply problems continued.
- Midwest states: at the request of eight states (Illinois, Iowa, Minnesota, Missouri, Nebraska, Ohio, South Dakota, and Wisconsin), EPA approved rules that let E15 be sold there in summer, starting in 2025 (with a later start in Ohio and parts of South Dakota).
- Congress: the House passed a bill for year-round E15 nationwide (H.R. 1346) in May 2026. When we checked in November 2026, we found no final law.
What this means for you: in winter, E15 is legal across the country; whether a station sells it is up to the station. For summer 2027, check EPA’s fuel waiver announcements in the spring. The rules decide what stations may sell; your manual decides what your car should use.
E85 and flex-fuel vehicles
E85 (also sold as “flex fuel”) is a blend with 51% to 83% ethanol; the share changes with the region and the season. Only flex-fuel vehicles (FFVs) are built for it. To tell if your vehicle is one, fueleconomy.gov suggests:
- A yellow gas cap, or a yellow ring around a capless filler (most carmakers since model year 2008, GM since 2006)
- An “E85,” “Flex Fuel,” or “FFV” badge on the body
- A label inside the fuel door
- The fuel section of the owner’s manual
Don’t put E85 in a car that isn’t a flex-fuel vehicle. Its manual lists the fuels it may use, and E85 isn’t one of them.
Ethanol has about one-third less energy than gasoline, so a flex-fuel vehicle gets roughly 15% to 27% fewer miles per gallon on E85, according to fueleconomy.gov. A truck that gets 20 MPG on gas might get about 15 to 17 MPG on E85.
Is E85 cheaper? The break-even price
E85 often costs less per gallon, but you need more gallons. Compare cost per mile, not price per gallon. Because you lose about 15% to 27% in MPG, E85 is cheaper per mile only when its price is at least that much below regular gas:
| Your flex-fuel vehicle’s MPG loss on E85 | E85 must cost less than |
|---|---|
| 15% (smallest loss) | $3.40 a gallon |
| 27% (largest loss) | $2.92 a gallon |
Regular at $3.995 a gallon, U.S. average, EIA, week of November 9, 2026. Break-even = regular price × (1 − MPG loss).
The best way to know your car’s loss is to measure it: run a tank of gas and a tank of E85 and calculate the MPG of each (our MPG calculator does the math). Then put each fuel’s price into the fuel cost per mile calculator. Fueleconomy.gov also lists the E85 MPG rating for each flex-fuel model.
Is E15 the same as 87 or 89?
No, they measure different things. E15 describes how much ethanol is in the fuel. 87 and 89 are octane ratings, which measure resistance to engine knock. Every pump shows the octane on its own label, so an E15 pump tells you both. Your owner’s manual gives a minimum octane and a maximum ethanol share; a fuel must meet both. Octane and the grades are explained in premium vs regular gas.
On MPG: fueleconomy.gov says vehicles typically go 3% to 4% fewer miles per gallon on E10 and 4% to 5% fewer on E15, compared with gas that has no ethanol. Between E10 and E15, the difference is small: about 1%. Weather and driving change MPG much more; see what is good gas mileage.
FAQ
Is E15 bad for my car?
EPA allows E15 in cars, SUVs, and light trucks from model year 2001 and newer. But your owner’s manual decides what your engine was designed for: if it lists E10 as the limit, use E10. Never use E15 in motorcycles, boats, small engines, or cars older than 2001.
Can I put E85 in a regular car?
No. E85 is only for flex-fuel vehicles. Look for a yellow gas cap or filler ring, an E85 or Flex Fuel badge, a fuel door label, or the fuel section of your owner’s manual.
Is E85 cheaper than gas?
Per gallon, often. Per mile, only if the price gap is bigger than your MPG loss, which is about 15% to 27% on E85. At $3.995 for regular, E85 has to cost less than about $2.92 to $3.40 a gallon to save money.
Does E15 get worse gas mileage?
Slightly. Fueleconomy.gov says vehicles typically get about 4% to 5% fewer miles per gallon on E15 than on gas with no ethanol, compared with 3% to 4% fewer on E10.
How do I know if my car is flex fuel?
Check for a yellow gas cap or a yellow ring around the filler, an E85, Flex Fuel, or FFV badge, a label inside the fuel door, or the fuel section of your owner’s manual.
Sources
- U.S. Department of Energy, Alternative Fuels Data Center, E15 (approved and prohibited vehicles and engines) (checked November 12, 2026): afdc.energy.gov
- Fueleconomy.gov, Ethanol (E85 ethanol content; MPG on E10, E15, and E85; energy content) (checked November 12, 2026): fueleconomy.gov
- Fueleconomy.gov, Flex-fuel vehicles (how to identify a flex-fuel vehicle) (checked November 12, 2026): fueleconomy.gov
- U.S. EPA, news release on the nationwide emergency fuel waiver for E15, March 25, 2026 (checked November 12, 2026): epa.gov
- Congressional Research Service, Year-Round Sale of E15, Insight IN10979 (summer season, 20-day waivers, H.R. 1346; updated June 5, 2026; checked November 12, 2026): congress.gov
- Congressional Research Service, Year-Round Sale of E15, IN10979, December 9, 2025 version (eight Midwest states; Ohio and South Dakota dates) (checked November 12, 2026): everycrsreport.com
- CBS News Minnesota (Associated Press), EPA approves year-round sales of higher ethanol blend in 8 Midwest states (the eight states; February 22, 2024; checked November 12, 2026): cbsnews.com
- Mazda, 2022 MX-5 owner’s manual, fuel requirements (ethanol limit) (checked November 12, 2026): mazdausa.com
- U.S. Energy Information Administration (EIA), Gasoline and Diesel Fuel Update, U.S. regular gasoline, week of November 9, 2026 (checked November 12, 2026): eia.gov