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Fuel guide · Michigan City Ford · Michigan City, IN
Octane Rating Explained: Regular vs. Premium Gas
The big number on the gas pump is the octane rating. Here is what it means, which grade your vehicle needs, what happens if you use a higher or lower grade, and which 2026 Ford models are listed for premium, using fueleconomy.gov, the U.S. Department of Energy and EPA fuel economy site.
87octane rating of regular unleaded gasoline in the U.S.
91 to 94octane rating of premium gasoline
3 of 622026 Ford listings on fueleconomy.gov listed for premium gasoline
About 109octane rating of ethanol, which refiners blend in to boost octane
The short answer
Octane rating measures how well a fuel resists engine knock. Regular gas is 87, midgrade 88 to 90 and premium 91 to 94. Use the octane your vehicle's manufacturer requires, as listed in your owner's manual. Using less than required can hurt power, mileage and the engine over time; using more than required may bring little to no benefit in normal driving. Of the 62 2026 Ford listings on fueleconomy.gov, three are listed for premium.
What octane rating means
Fueleconomy.gov defines octane rating as the measure of a fuel's ability to resist "knocking" or "pinging" during combustion. Knock is caused by the air/fuel mixture detonating prematurely in the engine.
At the pump, the octane rating is displayed in large black numbers on a yellow background.
From fueleconomy.gov's Selecting the Right Octane Fuel page, read November 8, 2026.
Regular, midgrade and premium
In the U.S., unleaded gasoline typically comes in three grades:
| Grade | Typical octane rating |
|---|---|
| Regular | 87 |
| Midgrade | 88 to 90 |
| Premium | 91 to 94 |
From fueleconomy.gov's Selecting the Right Octane Fuel page, read November 8, 2026. Gasoline rated 85 octane is available in some high-elevation areas of the U.S.
Which octane should you use?
Use what the manufacturer requires. Fueleconomy.gov says to use the octane rating your vehicle's manufacturer requires, so check your owner's manual. Most gasoline vehicles are designed to run on 87 octane, but others are designed to use higher octane fuel.
Why some engines need more. Higher octane fuels are often required or recommended for engines that use a higher compression ratio or use supercharging or turbocharging to force more air into the engine. Higher cylinder pressure lets the engine extract more energy from the air/fuel mixture, but it needs higher octane fuel to keep the mixture from pre-detonating. In these engines, high octane fuel improves performance and fuel economy.
Required vs. recommended. If your vehicle requires midgrade or premium fuel, fueleconomy.gov says the higher octane is absolutely worth the extra cost. If your owner's manual says premium is not required but the vehicle will run better on it, the choice is up to you.
From fueleconomy.gov's Selecting the Right Octane Fuel page, read November 8, 2026.
Using a higher or lower octane than required
Here is what fueleconomy.gov says happens when the octane at the pump does not match what your vehicle needs:
| Situation | What fueleconomy.gov says |
|---|---|
| Lower octane than required | The engine can run poorly, and over time it can damage the engine and emissions control system. It may also void your warranty. Older vehicles can make an audible knocking or pinging sound. Many newer vehicles adjust spark timing to reduce knock, but engine power and fuel economy still suffer. |
| Higher octane than required | For most vehicles, higher octane may slightly improve performance and gas mileage during severe duty, such as towing a trailer or carrying heavy loads, especially in hot weather. Under normal driving conditions, you may get little to no benefit. |
| Cost | The fuel components that boost octane are generally more expensive to produce. When premium is not required, the cost increase is typically higher than the fuel savings. |
From fueleconomy.gov's Selecting the Right Octane Fuel page, read November 8, 2026.
Ethanol and 85 octane
Ethanol: ethanol has a much higher octane rating (about 109) than gasoline, and refiners usually blend it with gasoline to help boost the octane rating. Most gasoline in the U.S. contains up to 10% ethanol. Blends of up to 15% ethanol are available in some areas, and several manufacturers approve that blend in recent-model vehicles.
85 octane: sale of 85 octane fuel was originally allowed in high-elevation regions, where barometric pressure is lower, because it was cheaper and most carbureted engines tolerated it fairly well. Fueleconomy.gov says that is not true for modern gasoline engines, so unless you have an older vehicle with a carbureted engine, use the manufacturer-recommended fuel even where 85 octane is available.
From fueleconomy.gov's Selecting the Right Octane Fuel page, read November 8, 2026.
2026 Ford models listed for premium gas
Of the 62 Ford listings for model year 2026 on fueleconomy.gov, 52 are listed for regular gasoline, 6 for electricity (Mustang Mach-E versions), 1 for regular gasoline and electricity (Escape FWD PHEV), and these 3 for premium gasoline. Names are as listed there; mpg is city / highway / combined:
| fueleconomy.gov listing | Engine | Transmission | EPA mpg |
|---|---|---|---|
| F150 RAPTOR R 4WD | 5.2L 8-cyl, supercharged | Automatic (S10) | 10 / 15 / 12 |
| Mustang Dark Horse SC | 5.2L 8-cyl, supercharged | Automatic (AM-S7) | 12 / 18 / 14 |
| Mustang GTD | 5.2L 8-cyl, supercharged | Automatic (AM-S8) | 10 / 17 / 12 |
From the 2026 Ford model listing and records 50104, 51093 and 50279 on fueleconomy.gov (U.S. DOE/EPA), read November 8, 2026. All 41 turbocharged 2026 Ford listings there, including turbocharged versions of the F150, Bronco, Explorer, Expedition, Ranger, Maverick, Escape and Mustang, are listed for regular gasoline. EPA ratings are for comparison; your mileage will vary. Your owner's manual is the final word on the fuel your vehicle requires or recommends.
Maintenance and service at Michigan City Ford
The Works® at Michigan City Ford includes a synthetic blend oil change, tire rotation and pressure check, brake inspection, Multi-Point Inspection, fluid top-off, battery test, and a filter, belts and hoses check. Not sure which fuel your Ford takes, or hearing a knock? Our service team can help.
Schedule service online and see our service specials first. Michigan City Ford is at 3930 Franklin St. in Michigan City. Get directions.
Michigan City Ford service hours
| Days | Hours |
|---|---|
| Mon-Fri | 7:30 a.m.-5:30 p.m. |
| Sat | 8 a.m.-3 p.m. |
| Sun | closed |
From Michigan City Ford's website, November 8, 2026. Holiday hours can differ.
Octane rating FAQ
What is an octane rating?
Fueleconomy.gov defines octane rating as the measure of a fuel's ability to resist "knocking" or "pinging" during combustion, caused by the air/fuel mixture detonating prematurely in the engine.
What octane is regular, midgrade and premium gas?
In the U.S., unleaded gasoline typically has octane ratings of 87 (regular), 88 to 90 (midgrade) and 91 to 94 (premium), according to fueleconomy.gov. The rating is shown in large black numbers on a yellow background on the pump.
Should I use premium gas if my car only needs regular?
Under normal driving conditions you may get little to no benefit, says fueleconomy.gov. Higher octane may slightly improve performance and gas mileage during severe duty such as towing a trailer or carrying heavy loads, especially in hot weather, but the cost increase is typically higher than the fuel savings.
What happens if I use regular in a car that requires premium?
Using a lower octane fuel than required can make the engine run poorly and can damage the engine and emissions control system over time. It may also void your warranty. Many newer vehicles can adjust spark timing to reduce knock, but engine power and fuel economy will still suffer.
Which 2026 Ford models are listed for premium gas?
Of the 62 Ford listings for model year 2026 on fueleconomy.gov, three are listed for premium gasoline: the F150 RAPTOR R 4WD, the Mustang Dark Horse SC and the Mustang GTD, each with a supercharged 5.2-liter 8-cylinder engine. The rest are listed for regular gasoline, electricity, or regular gasoline and electricity.
Do turbocharged engines need premium?
Fueleconomy.gov says higher octane fuel is often required or recommended for engines with a higher compression ratio or with supercharging or turbocharging. Even so, all 41 turbocharged 2026 Ford listings on fueleconomy.gov are listed for regular gasoline. Your owner's manual is the final word for your vehicle.
Is 85 octane gas safe to use?
Fueleconomy.gov says 85 octane was originally allowed in high-elevation regions because most carbureted engines tolerated it fairly well, which is not true for modern gasoline engines. Unless you have an older vehicle with a carbureted engine, use the manufacturer-recommended fuel.
Does ethanol raise octane?
Yes. Ethanol has a much higher octane rating (about 109) than gasoline, and refiners usually blend it with gasoline to help boost the octane rating. Most U.S. gasoline contains up to 10% ethanol.
Questions about your fuel?
Schedule service with the Michigan City Ford team, or read our guide to getting better gas mileage.
Sources
What octane rating means, the U.S. gasoline grades, which octane to use, the effects of using higher or lower octane, and the ethanol and 85 octane notes are from fueleconomy.gov, administered for the U.S. Department of Energy and the EPA, read November 8, 2026. The 2026 Ford fuel types and EPA ratings are from the same site's model listing and vehicle records, read the same day. Service details, address and hours are from Michigan City Ford's own website.
- fueleconomy.gov, Selecting the Right Octane Fuel, fueleconomy.gov (U.S. DOE/EPA), read November 8, 2026
- 2026 Ford model listing (44 model names; fuel type and engine from the 62 vehicle records), fueleconomy.gov (U.S. DOE/EPA), read November 8, 2026
- 2026 Ford F150 RAPTOR R 4WD, Mustang Dark Horse SC and Mustang GTD: fuel type and EPA mpg (records 50104, 51093, 50279; link opens record 50104), fueleconomy.gov (U.S. DOE/EPA), read November 8, 2026
- General service: The Works, Michigan City Ford, November 8, 2026
- Address and service hours (structured data), Michigan City Ford, November 8, 2026