Is Costco Gas Bad For Your Car?

Costco is renowned for having great deals on many of your daily necessities, including gas! So, you might want to visit Costco if you wanted to fill up your tank at a fair price. However, you’ll first be doubting the quality of Costco gas.

After doing some research, and here’s what CarMats found out.

Is Costco Gas Good?

Kirkland Signature gasoline, which is sold under the Costco brand, is thought to be of high quality. It is “top-tier” standard gasoline, which means that it has more additives than the US government requires. Costco also sells gas at a lower price per gallon than most of its competitors.

So how much does Costco’s premium gas cost? And why are the prices so low, exactly? Everything you need to know, including costs, comparisons, drawbacks, and other crucial details, is right here.

How Much Does Costco Gas Cost?

The price of Kirkland Signature gas sold by Costco will vary depending on a number of uncontrollable factors, just like the price of other types of gas.

Despite price fluctuations, Costco is able to maintain lower prices than other gas stations. A 2018 study found that Costco’s gas is generally about 21 cents less expensive per gallon than its rivals.

According to information from other platforms, the price difference is more like 10 or 15 cents. In either case, the cost per gallon accumulates and can result in some significant savings.

Why Are Costco Gas Prices So Low?

Because it charges members a membership fee, Costco is able to maintain gas prices at such impressively low levels. The Kirkland Signature gas sold by Costco is only available to members.

Depending on the benefits you want, a personal membership can cost anywhere from $60 to $120 annually. Costco gets about 75% of its money from membership fees, which lets the store keep prices low on everything from groceries to gas. But unless you fill up your car at Costco a lot, it’s unlikely that the membership fee will be worth it.

If you only use your Costco membership to access fuel, it appears that you would need to refuel at Costco 35 or more times a year to cover the cost of the membership.

Costco Gas Vs Shell, Mobil, Texaco, Chevron, & Exxon

Some posts on Reddit say that Costco gas is almost as good as gas from Shell, Mobil, Texaco, Chevron, and Exxon. Some Reddit users also say that Costco buys gas from these refineries and rebrands it as Kirkland.

The only real distinction between Costco gas and, say, Shell gas is that Costco adds fuel additives locally rather than at the refinery fuel rack (to save money). Also, Costco gas meets the same standards for additives set by the US government as Mobil, Texaco, and Shell gas.

Does Costco Gas Have Ethanol?

Online reports claim that because Costco 91 unleaded gasoline is a “Top Tier” fuel, it does not contain ethanol. However, Costco’s Kirkland Signature brand gasoline does meet the Energy Independence Act’s 10% ethanol requirement. Additionally, the mix of fuel will be added to all of the pumps when you fill up at Costco Gas.

Is Costco Gas Bad For Your Car?

Your car won’t be ruined by Costco gas, for sure!

In fact, Kirkland Signature gas has a lot of detergent additives in it, which helps to improve both the engine’s cleanliness and the quality of the gas in your car. This indicates that it qualifies as top-tier fuel.

Or, to put it another way, Costco’s gas meets or exceeds the minimum additive standards established by the Environmental Protection Agency of the US government.

The difference between so-called “Top Tier” gas and gas that only satisfied the minimum standards set by the government was compared by AAA. They also found that engines that used top-tier fuel had intake valve deposits that were 19 times less common.

Is Costco’s Regular Gas As Good As Premium Gas?

You can be confident that the Kirkland Signature gasoline you purchase from Costco, whether it is regular or premium, will be of the highest quality.

The total amount of detergent additives in the fuel sold at Costco gas stations is higher than average.

As a result, top-tier requirements are met by Costco’s premium and regular gas.

Other than that, the only difference between regular and premium Kirkland Signature gas is the octane level. Always fill up with the octane level recommended in your car’s owner’s manual.

What Other Gas Stations Offer “Top Tier” Gas?

There are numerous other gas stations in the US besides Costco that sell fuel that complies with Top Tier standards.

This is used to describe fuel that exceeds the minimum standards set by the US government for fuel quality.

Visit the Top Tier Gas website to learn more about their exacting requirements.

As of January 2020, the following retail companies have gas stations where they sell top-tier fuel:

  • 76
  • ARCO
  • BP
  • Chevron
  • Esso
  • Mobil
  • Shell
  • Texaco
  • Wow

Local convenience stores that sell Top Tier licensed fuel may also exist. So, besides Costco, there are many other places where you can buy certified high-quality fuel. The likelihood is that Costco’s prices will be significantly less expensive per gallon.

Is Costco Gas Popular?

Yes, Costco gasoline is very well liked, and it’s easy to understand why. Kirkland Signature gas from Costco is not only the best, but it is also often the cheapest option. But in many ways, its popularity is also its biggest flaw.

You’ll probably have to wait in line quite a while to fill up your car with Costco fuel. Gas station lines at Costco are well-known. You might even have to wait for an hour!

While you wait, someone in the car could always run into the Costco warehouse to do any necessary shopping. Check out my posts on the Costco Cash Card, whether Costco Gas accepts credit cards, and the Costco Gas hours if you’re interested in giving them a try.


Costco gas stations sell Kirkland Signature gas, which is of excellent quality and a great price.

Both the premium and regular gas at Costco meet strict Top Tier performance standards. This is because both types of gas contain a lot of detergent additives. And it still manages to have a lower price per gallon than many of its closest rivals by a few cents.

The only bad things about getting gas from Costco are the long lines at the pumps and the need to pay an annual membership fee. The advantages, however, far outweigh the disadvantages.


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