Which credit card should I use at Costco?
In a US Costco warehouse you need a Visa, and the purchase codes as a wholesale club rather than a grocery store, so your best choice is usually the Visa with the highest flat rate, or a Visa that specifically bonuses wholesale clubs. Costco.com accepts Mastercard and Discover too, and gas pumps code as fuel.
Costco is the store where more people pull out the wrong card than anywhere else, for two reasons that have nothing to do with rates: the network restriction and the merchant code.
Rule one: Visa at the register
US Costco warehouses accept Visa credit cards and no other credit network. A Mastercard, an American Express or a Discover card is declined at the register, regardless of how good its grocery rate is. Debit cards on any network and Costco Shop Cards work.
Costco.com is broader: Visa, Mastercard and Discover are accepted online, but still not American Express.
Outside the US, the accepted network differs by country. This post is about US warehouses.
Rule two: it is not groceries
Costco carries a wholesale club merchant category code. Most cards with a grocery bonus exclude warehouse clubs explicitly, and the few that do not still will not see a supermarket code. So the 4x or 6 percent grocery rate on your favourite card does not apply here, even if you bought only food.
That turns the question into a simpler one: among your Visas, which earns the most on a general purchase, or specifically on wholesale clubs?
How to pick
- List your Visas. Everything else is out at the register.
- Compare their flat or wholesale-club rates. A 2 percent flat-rate Visa typically beats a premium travel Visa earning 1x on general spend, unless you value the travel points above 2 cents each.
- Check for a credit. A few cards carry wholesale club or membership credits. A credit on today’s purchase beats any rate difference.
- Remember the cap. If your best Visa has a cap on its bonus category, make sure you are still under it.
splurn does this automatically. It knows Costco is Visa-only, greys out the cards that will not work, counts the purchase as a wholesale club, and ranks what is left. If the code it guessed is wrong for your location, change it once under “Counted as” and it remembers.
Gas, pharmacy and food court
- Gas pumps code as fuel stations. Cards with a gas bonus generally earn it, and the Visa rule still applies.
- The pharmacy rings through the same warehouse system, so expect the wholesale club code.
- Food court purchases code as the warehouse too, not as a restaurant.
Online is different
Costco.com takes Mastercard and Discover as well as Visa, which re-opens the comparison. Online purchases still code as a wholesale club, so the grocery exclusion remains. Some cards bonus “online retail” or “wholesale clubs” specifically; check yours.
The short version
- In a US warehouse: Visa only, coded as a wholesale club.
- Use your highest flat-rate Visa unless one bonuses wholesale clubs or carries a credit.
- Gas is gas. Online adds Mastercard and Discover but stays a wholesale club.
Quick answers
Does Costco accept American Express?
Not in US warehouses or on Costco.com. US Costco locations accept Visa credit cards at the register; Costco.com also takes Mastercard and Discover. Debit cards and Costco Shop Cards work everywhere.
Does Costco gas count as gas on my card?
Usually yes. Costco fuel stations carry a fuel merchant code, so cards with a gas bonus generally earn it there. Check your card's terms for any exclusion of warehouse club fuel.
Does the Costco Anywhere Visa earn a bonus inside Costco?
Its warehouse rate is lower than its restaurant, travel and gas rates. Compare it to your other Visas' flat rates before assuming it wins inside the store.
splurn is not a bank, issuer or lender, and is not affiliated with any issuer. Card terms change; confirm rates, credits and fees in your card's current terms before relying on them.