Is Costco Gas Good? (Top Tier, Who Makes It + More!)

Costco is famous for offering great prices on loads of your everyday essentials – gas included!

So, if you wanted to top up your tank at a reasonable cost, you might want to go to Costco. But first, you’ll be wondering whether Costco gas is actually any good.

I’ve done plenty of research, and here’s what I found out.

Is Costco Gas Good?

Costco’s own-brand Kirkland Signature gas is considered excellent quality and is “Top Tier” standard gasoline, meaning it far surpasses US government additive requirements. Additionally, Costco sells gas at several cents less per gallon than their average competitors.

So, how much does high-quality gas cost at Costco? And why, exactly, are the prices so low?

I’ve got everything you need to know right here, including costs, comparisons, drawbacks, and other important information.

How Much Does Costco Gas Cost?

As with all other gas prices, the exact cost of the Kirkland Signature gas sold at Costco will vary depending on several factors beyond the retailer’s control.

However, Costco is able to keep prices lower than other gas stations, regardless of how they fluctuate.

According to a 2018 report, Costco’s gas costs an average of around 21 cents less per gallon than its competitors.

Other platforms have reported that the price difference is closer to around 10 or 15 cents. Either way, the price per fill-up adds up and can amount to some impressive savings.

Why Are Costco Gas Prices So Low?

Why Are Costco Gas Prices So Low?

Costco can keep gas prices so impressively low because it charges those who use it a membership fee. Only people who are Costco members can buy Costco’s Kirkland Signature gas.

A personal membership costs between $60 and $120 per year, depending on the benefits you want access to.

The price of membership accounts for around 75% of Costco’s profits, which allows the chain to keep prices low on everything from gasoline to groceries.

However, unless you fill your car up at Costco regularly, you are unlikely to make the price of the membership worthwhile.

Apparently, to make up the cost of the membership, you would have to refuel at Costco around 35 or more times a year, assuming you only use your Costco membership to access fuel.

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

According to some Reddit threads, Costco gas is essentially the same quality as many gas companies, including Shell, Mobil, Texaco, Chevron, and Exxon.

Additionally, some Reddit users believe Costco buys their gas from these very refineries and renames it under their own Kirkland brand.

The only real difference between Costco gas and, say, Shell is that Costco adds fuel additives on site (to save money), as opposed to the refinery fuel rack.

Additionally, Costco gas also meets the same US government additive requirements as Mobil, Texaco, and Shell.

Does Costco Gas Have Ethanol?

According to online reports, Costco 91 unleaded gas does not have ethanol as it is a “Top Tier” gasoline.

However, Costco’s Kirkland Signature brand gasoline does contain 10% ethanol in requirement with The Energy Independence.

Additionally, when filling up at Costco Gas, all pumps will have the mix of fuel added.

Is Costco Gas Bad For Your Car?

Costco gas definitely does not ruin your car!

In fact, Kirkland Signature gasoline contains high quantities of detergent additives, which help to improve the quality of the gas in your car as well as the cleanliness of the engine.

This means it can be classed as Top Tier gasoline.

Or, in other words, Costco’s own-brand gas surpasses the minimum additive requirements set by the US government’s Environmental Protection Agency.

AAA studied the difference between so-called Top Tier gas and gas that merely met the government’s minimum requirements.

Additionally, they found that engines that ran on Top Tier fuel averaged 19 times fewer intake valve deposits.

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

Whether you buy regular or premium Kirkland Signature gasoline from Costco, you can be sure you’re filling up your car with great-quality fuel.

All the fuel sold at Costco gas stations has higher than average quantities of detergent additives.

So, both Costco’s premium and regular gas meet Top Tier standards.

Beyond that, the only difference between premium and regular Kirkland Signature gas is octane levels.

Always refuel with the octane levels specified in the owner’s manual of your car.

What Other Gas Stations Offer “Top Tier” Gas?

What Other Gas Stations Offer “Top Tier” Gas?

Aside from Costco, there are plenty of other gas stations in the US that sell fuel that meets Top Tier standards.

This refers to fuel that is of a higher standard than the US government’s minimum requirements for fuel quality.

For a better understanding of their stringent specifications, visit the Top Tier Gas website.

As of January 2020, some of the retail brands that sell Top Tier fuel at their gas stations include:

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

There may also be local convenience stores that sell Top Tier licensed fuel. So, in addition to Costco, you can purchase certified high-quality fuel from lots of different locations.

However, the chances are that Costco’s prices will be significantly lower per gallon.

Is Costco Gas Popular?

Yes, Costco gasoline is very popular – and it’s not hard to see why! Not only is Costco’s Kirkland Signature gas of the highest quality, but it is also very often the cheapest option.

However, its popularity is, in many ways, its biggest drawback.

You will more than likely have to wait in line to refill your car with Costco fuel and for quite a long time. Costco’s gas station lines are notorious. You could even end up waiting an hour!

However, you could always have someone in the car run into the Costco warehouse to do any necessary shopping while you wait.

If you are interested in trying Costco Gas, don’t forget to see my posts on Costco Cash Card, if Costco gas takes credit cards and the Costco Gas opening hours!


The Kirkland Signature gasoline sold at Costco gas stations is both high quality and great value for money.

The high quantities of detergent additives in both Costco’s premium and regular gas means it meets strict Top Tier performance standards.

And, it still manages to be several cents cheaper per gallon than many of its closest competitors.

The only downsides to filling up your car with Costco gas are the long lines at the gas stations and the annual membership fee you have to pay to use it.

However, the benefits far outweigh the drawbacks.

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Marques Thomas

Marques Thomas graduated with a MBA in 2011. Since then, Marques has worked in the retail and consumer service industry as a manager, advisor, and marketer. Marques is also the head writer and founder of

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