Costco Gas Calculator: Will I Save Money Buying a Membership if All I Buy is Fuel?

Costco gas fuel calculator
For those who don’t shop at Costco regularly enough to make a membership worthwhile, it might be worth getting one if your Costco has a gas station, and you fill up your vehicle on a regular basis. The question you should be asking yourself is, “Will I save money if I get a Costco membership simply from the money I save on gas?”

There are quite a few variables that go into this calculation, and you’re going to have to make some estimates to decide if you’ll receive enough savings by filling up your cars with fuel there instead of at other gas stations in the area. For instance, the price difference between Costco and where you regularly fill up your car will fluctuate throughout the year. In this case, you can use the difference in price right now to make the estimate, or you can go with a general guess of the difference in prices throughout the year. This can vary quite dramatically depending on where you live. I have found that when looking at the prices around my area, Costco gas is usually around $0.15 less per gallon than other local gas stations. I have also seen it as much as $0.30 below the going rate around it, and as little as seven cents.

The other estimate you need to make is the number of gallons of gas you buy each week. You can keep track of this for a week, or do a good estimate from your past experience. Insert these two numbers into the simple Costco Gas Calculator below then hit “calculate,” and you’ll know if you’ll end up saving money by purchasing a membership at Costco.

Costco Gas Savings Calculator
How many gallons do you use in a week?

How much cheaper is Costco’s gas compared to the next cheapest option?

This is a simple formula (gallons purchased per week x cost difference x 52.1775 weeks per year) that should give you a general idea of whether or not it makes sense for you to purchase a membership on the gas savings alone. Costco’s gas is comparable to other top brand fuel, but it’s still usually less expensive than the lowest off-brand fuel being sold. Here are a few other things that you need to consider that might sway the decision one way or the other if your calculations come out almost even.

Will You Shop Sometimes?

If you can basically break even for the membership with the savings when purchasing gas, would a free membership to the warehouse save you money? If you weren’t interested in paying for a membership in the past because you wouldn’t use it enough, that doesn’t mean that you wouldn’t use it at all if it were free. This might result in additional savings that makes getting a membership worthwhile. On the other hand, it could also cost you more depending on how you shop.

Is the Station out of the Way?

If your nearest Costco store is nearby, or along a route that you drive on a regular basis, then there’s no additional calculations that you need to make. If, however, you must drive out of your way to get to Costco, you need to estimate the extra monetary and time cost of driving those extra miles when making the calculation. A more expensive station might actually cost less if you have to drive out of your way to use the Costco station.

Do you have a cash back Credit Card?

If you use a cash back credit card to get additional savings at gas stations, you need to take this into consideration as well. You can’t use a cash back credit card at Costco gas stations, so you will forfeit the savings from using it. This can be a significant amount. If you have a credit card that gives 3% to 5% cash back at gas stations, that’s a $0.12 to $0.20 savings a gallon when gas costs $4.00.

In the end, there’s going to be a lot of personal factors that determine whether getting a membership makes sense. Those with bigger vehicles, multiple vehicles or long commutes will find that getting a membership makes sense, while someone with a short commute and a fuel-efficient car might not. In the end, input your numbers, and the calculator will give you a good sense of the savings you might see, and an opportunity to consider a bit more critically if the savings make sense or not.

(Photo courtesy of terrykimura)

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5 Responses to Costco Gas Calculator: Will I Save Money Buying a Membership if All I Buy is Fuel?

  1. NJDebbie says:

    Our local Costco does not require a membership to purchase their gas. You simply need a debit card because cash is not accepted.

  2. jeffrey says:

    This is definitely not the norm. Most will require that you swipe your Costco membership card first before your debit card in order to get gas.

  3. Kiki says:

    My Costco is about 2 miles from my house. It sits on a corner lot with a Shell and Arco stations directly across from it. The process for gas is almost always the same at the Arco and 10 or so cents cheaper than Shell. It is always one of the cheapest stations around the area.

    That being said I drive a Prius and fill up maybe twice a month. Three times only if I have a meeting in the bay area for work. I spend about $50 for gas in a month. It would take me forever to make up the $55 fee to join.

    I do not have a current membership, and don’t plan to sign up for one any time soon.

  4. forto says:

    So if you use 10 gallons a week, then there needs to be about a 11 cent difference to break even. I’ll have to keep a closer look at prices this month to see if it makes sense or not.

  5. Jerry says:

    Not worth it. I have found that sometimes it is only 2 or 3 cents lower. Never have I seen it more than 10 cents per Gal.

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