What Is Premium Gas? Octane, Who Needs It and Mixing Grades

Published Oct 23, 2026 · 5 min read · By Hassan, Owner of Roadmate Services

What is premium gas? It is gasoline with an octane rating of 91 or higher. At many Ohio stations that means the 93 button. Regular is 87 and midgrade sits in between, according to fueleconomy.gov.

Higher octane does not mean cleaner or stronger gas. It means the fuel resists knocking in engines built to need it. If your car is not one of them, AAA’s testing found premium gives you nothing back.

The premium button is the first-class seat of the gas pump. Same trip, same arrival time.

Quick answer: regular, midgrade and premium at a glance

Sources: fueleconomy.gov, AAA. Checked October 2026.

What is octane, and why does premium have more?

Octane measures how well fuel resists knocking, or pinging: the air and fuel mix igniting too early in the cylinder. You hear it as a rattle under load, like on a hill or a merge.

High-compression and turbocharged engines squeeze the mix harder, so they need fuel that holds off longer. That is the whole job of premium. Octane is not a vitamin: more of it does not make a healthy engine healthier.

Is 93 premium gas?

Yes. Premium covers 91 to 94 octane, and which number you see depends on where you fill up. Many Columbus stations sell 87, 89 and 93. Some states top out at 91, so a 91 there is the same grade as a 93 here.

In some high-elevation areas you may see 85. Fueleconomy.gov says modern engines do not handle it well, so stick with your manual’s grade on a trip out west. The numbers change by state. The pump etiquette does not.

Does your car need premium gas? Required vs recommended

Check the owner’s manual or the label inside the fuel door. The wording matters more than the badge on the trunk.

“Premium required”

Use premium every time. The U.S. Department of Energy counted 22% of model year 2022 car and light truck models in this group.

“Premium recommended”

Regular is allowed. The engine runs on it with a little less power and mileage. Fueleconomy.gov calls this one your choice, and notes the extra cost usually beats the fuel savings.

Regular (87) only

Premium is wasted money. AAA tested 87 against 93 in cars built for regular and found no real gain in horsepower, fuel economy or emissions. Your car will not notice the upgrade. Your bank statement will.

What happens if you use the wrong grade?

Premium in a regular car: nothing bad. You paid extra, and the car drove exactly the same.

Regular in a premium-required car: most newer engines pull back the spark timing to stop knock. The car runs, but with less power and worse mileage. Fueleconomy.gov warns that doing it over time can damage the engine and the emissions system. One tank by mistake is not a disaster.

Hear steady knocking, or see a check engine light, after a fill-up? That is a job for a mechanic, not for roadside help, and we will tell you so. Diesel in a gas tank is a different and bigger problem, covered in what to do if you put diesel in a gas car.

Can you mix premium and regular gas?

Yes, and it is safe for any gasoline car. The grades blend to an octane somewhere in between. As Jerry puts it, half a tank of 87 plus half a tank of 93 is roughly a tank of 90.

In a premium-required car, a mixed tank counts as a lower grade, so drive gently and top off with premium soon. Think of it as half-caf for your engine.

Out of gas in a premium car?

If you are on a highway shoulder, get safe first: pull as far right as you can, turn on your hazards and stay buckled in, or wait behind the guardrail if you can get there safely. Then call. Our guide on what to do if you run out of gas has the full steps.

In Columbus, our fuel delivery brings regular or premium gasoline, or diesel, usually 2 gallons, or as much as you ask for. Tell the dispatcher your car takes premium and we bring premium. If you are in a hurry and regular is what you can get, a couple of gallons of it will still reach a station; drive gently, then fill up with premium there.

One driver passing through Columbus on his way to Indianapolis ran completely dry on a highway shoulder in the middle of the day. We arrived in about 30 minutes and got him back on the road.

4 things to check before you pay for premium

1. The fuel door label or the owner’s manual: required, recommended or regular.
2. If premium is only recommended, whether you tow or carry heavy loads often. That is when it helps most.
3. Knocking on regular. If you hear it, try the grade the manual names.
4. The brand, not just the grade. AAA says a Top Tier detergent gasoline matters more for engine deposits than extra octane.

If the label says 87 and the car runs quietly, you do not need us or a mechanic for any of this. Fill up with regular and keep the difference.

Frequently asked questions

More fuel guides: is driving on empty bad; E10, E15 and ethanol-free gas; red (off road) diesel.

The bottom line

Premium gas is 91 octane or higher, and 93 is premium. It matters only for engines that require or recommend it; everything else should run on regular. Mixing grades is safe.

As Hassan puts it: “Most fuel calls happen on the highway, when the driver has not paid attention to the gas gauge. Please look at it.” Whatever the grade, it works best inside the tank.

May your fuel gauge stay closer to F than to the little orange light.