As Kansas pushes more ethanol-blended fuel, drivers need to know what the numbers at the pump really mean — and which gas actually saves money.
Many drivers pull up to the gas pump and make the same quick decision every week: regular, mid-grade, premium — or maybe that cheaper “Unleaded 88” option.
But as gas prices continue to rise, that decision feels a lot less routine.
When filling up starts costing $50, $70, or more, many drivers begin asking the same question: Can I save money by switching to a cheaper fuel option?
Should you move from premium to regular? Is Unleaded 88 a better deal? Does cheaper gas actually save money, or just look better on the pump?
At the same time, Kansas is encouraging the sale of more ethanol-blended fuel through a new tax credit for retailers, which means more drivers may soon see even more fuel choices at gas stations.
The problem is, many people assume higher numbers mean better gas, or that cheaper fuel always saves money. Neither is necessarily true.
Understanding the difference between octane and ethanol can help drivers make smarter decisions for both their vehicles and their wallets.
What Kansas Just Did
Gov. Laura Kelly recently signed Senate Bill 82, which includes a tax credit for gas stations that sell E15 and higher ethanol blends.
Retailers can receive a 5-cent-per-gallon state tax credit for selling fuels like E15 — gasoline blended with 15% ethanol instead of the more common 10%.
The goal is to encourage more stations to offer higher-ethanol fuel, support Kansas corn farmers and ethanol producers, and give drivers more lower-cost fuel options.
Kelly said the move is designed to help both consumers and agriculture.
“Authorization of year-round E15 sales will create increased domestic demand for Kansas corn and grain sorghum while lowering gas costs for Kansans,” Kelly said.
But lower cost at the pump does not always mean lower cost to drive.
Octane and Ethanol Are Not the Same
This is where many drivers get confused.
The numbers 87, 89, and 93 usually refer to octane.
E10, E15, and E85 refer to ethanol content.
They are not the same thing.
A simple way to remember it:
If it starts with an “E,” it is talking about ethanol.
If it is just a number on the pump — 87, 89, 91, or 93 — it is talking about octane.
Octane measures how resistant fuel is to engine knocking — when fuel ignites too early inside the engine. Higher-performance engines often require higher-octane fuel to prevent damage and keep the engine running properly.
That is why some vehicles require premium gas.
Ethanol, on the other hand, is the amount of alcohol blended into gasoline.
For example:
E10 means 10% ethanol and 90% gasoline.
E15 means 15% ethanol and 85% gasoline.
E85 means 51% to 83% ethanol and is only for flex-fuel vehicles.
Many people assume premium gas is ethanol-free. It usually is not.
Most 87, 89, and 93 octane fuels sold at regular gas stations still contain up to 10% ethanol unless they are specifically labeled “ethanol-free.”
The number 93 has nothing to do with ethanol percentage. It refers only to octane — how the fuel performs inside your engine.
That means premium 93 can still contain the same E10 blend as regular 87.
Higher octane does not mean less ethanol.
Why Ethanol Was Added to Gas
Ethanol became common for both environmental and economic reasons.
It began replacing MTBE, another gasoline additive that was phased out because it contaminated groundwater.
Ethanol helps gasoline burn cleaner and also boosts octane naturally.
It also supports American agriculture, especially in corn-producing states like Kansas.
The federal Renewable Fuel Standard, passed in 2005 and expanded in 2007, helped make ethanol-blended gasoline the national standard.
Today, most gasoline sold in the U.S. contains some ethanol.
What About E85 and Flex-Fuel Vehicles?
This is another area where drivers get confused.
E85 often has an octane rating over 100, which makes some people think it must be the “best” fuel.
But high octane does not automatically mean better.
E85 contains much more ethanol and less energy per gallon, which means most drivers get significantly fewer miles per tank.
It is also only designed for flex-fuel vehicles — cars and trucks built with fuel systems and sensors that can safely handle high ethanol blends.
Even if you own a flex-fuel vehicle, E85 may not be your best everyday choice.
Many drivers see a 15% to 30% drop in fuel economy with E85. If the price difference at the pump is small, the lower mileage can wipe out the savings.
That is why many flex-fuel drivers only use E85 when the price gap is large enough to make it worthwhile.
Which Gas Should You Choose?
For most drivers, regular 87 octane is the correct choice.
That is what most standard passenger vehicles are designed to use.
AAA puts it simply: “Using a higher octane fuel than your vehicle requires offers no benefit.”
Using premium 91 or 93 when your manufacturer only recommends 87 usually does not improve mileage enough to justify the extra cost.
It mostly just costs more.
Likewise, E15 — often sold as Unleaded 88 — may be cheaper per gallon, but ethanol contains less energy than straight gasoline.
That means your miles per gallon may drop slightly.
You may save money at the pump but still spend the same — or more — over time if you are filling up more often.
How to Know What Your Car Needs
The best place to check is your owner’s manual.
It will tell you:
the minimum octane required
whether E15 is approved
whether your vehicle is a flex-fuel vehicle
You can also often find this information printed inside the fuel door or on the gas cap.
If your gas cap says “E85/Gasoline,” your vehicle is flex-fuel.
If it does not, do not use E85.
Most vehicles made in 2001 or newer can safely use E15, but checking first is still important.
The Car Care Council puts it simply: “The best fuel for your vehicle is the one recommended by the manufacturer.”
How to Test What Saves You the Most
The smartest way to compare fuels is not by price per gallon — it is by cost per mile.
This is the real way to know whether a cheaper fuel is actually saving you money.
As fuel economy experts often remind drivers: “Don’t judge fuel by the pump price alone—look at the cost per mile.”
Start by using your normal fuel for at least two full tanks and track:
price per gallon
total gallons filled
total cost
miles driven before your next fill-up
Then repeat the same test using another approved fuel option, like E15.
Divide your total fuel cost by the number of miles driven.
That gives you your true cost per mile.
A cheaper price at the pump may not mean real savings if that fuel gives you fewer miles per tank.
For example, saving 20 cents per gallon may not matter if you are filling up much more often.
Many drivers never test this and simply assume the lower pump price means savings.
Often, it does not.
The Biggest Mistake Drivers Make
Many drivers assume “premium” means better.
It does not.
Premium simply means higher octane for engines that require it.
And many drivers see “Unleaded 88” and assume it is premium gas.
It is not.
It usually means E15 — more ethanol, not necessarily better performance.
The best fuel is not the most expensive one.
It is the one your vehicle was designed to use.
As Kansas expands ethanol options, understanding what is actually coming out of the pump may matter more than ever.
