Everyone has their quirks
Here’s Why Costco’s Milk Containers Are Shaped Like That
Published on Jul. 16, 2025
Listen, even the most seemingly perfect of things has its quirks—it’s what makes the world go round. And Costco, for everything it does so absolutely right, definitely has a few of its own oddities. Case in point: Why are Costco’s milk containers shaped like that? If you’ve ever even glanced at them, you know they are atypical. These plastic jugs are weirdly boxy instead of being rounded like, well, a normal milk jug! Thankfully, this has nothing to do with the quality of Costco milk, but still, what is going on here?
Costco keeps prices low, regardless of skyrocketing inflation and the threat of tariffs, so it’s really hard to find much fault with them. But it’s natural to want some things to evolve, even just a little. And if those Costco milk containers are at the top of your list, you’re not alone. But there’s a reason for their unique shape, so let’s learn a bit more … and maybe help you dislike them a little less. Read on for the details.
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Why are Costco’s milk containers shaped like that?
It’s not because some head honcho has a fascination with square milk jugs that have an awkwardly placed, inset spout. Here’s the deal:
Efficiency
Sometimes functionality exceeds fashion, especially in a warehouse club. “Costco’s boxy milk jugs allow them to be stacked and shipped without crates, which saves space and reduces costs,” says John Anthony, owner of Andex, a company that specializes in packaging and the strategies behind it. “It’s a very warehouse-friendly design, even if it’s not the most user-friendly at home.”
Reduces cost
This, in turn, helps keeps costs low, since the milk is easier to stack on shelves and ships more efficiently. “While less appealing in design compared to the rounded conventional milk jugs found in most grocery stores, the square shape allows Costco to reduce their prices on milk because it improves shipping and storage efficiency,” says food scientist and food-industry consultant Bryan Quoc Le, author of 150 Food Science Questions Answered.
Is all of Costco’s milk like this?
No, not all Costco’s milk is sold in these square-ish plastic containers. However, much of it is. Kirkland Signature milk is largely carried in these square gallon containers. However, the Kirkland Signature A2 Organic Whole Milk, Half Gallon, 4 ct. is sold in typical carton form. The same is true of the Kirkland Signature Organic Milk 1% Low Fat Half Gallon, 3 ct. Maybe it’s because they are sold in groups of either three or four, and in half gallons, but these have the form of packaging the average grocery-store shopper is used to.
As one of our editors also noticed recently on a shopping trip, Costco also carries the “normally shaped” large plastic jugs as well, at least at some locations.
What do Costco shoppers think of these boxy milk jugs?
To be honest, Costco shoppers generally aren’t thrilled with the ill-fitting square milk jugs from Costco.
“They are too tall,” said one Redditor. “Have to shove them in my fridge and they lift the shelf up.”
Another echoed this sentiment: “Sam’s Club is the same. I drink it directly from the jug, and this shape is the worst,” they said. “The flat part on the top makes it way harder to drink because it smushes into your nose! I WANT REGULAR JUGS!”
On Reddit, a dairy worker tried to explain: “Previous dairy worker here. The company I used to work for (producers of dairy) put in special blow mold machines (they make gallon jugs) so that you can stack the jugs without any slip sheet or cardboard. Costco signed a huge deal with them almost 10 years ago, giving them tons of money to expand facilities and accommodate these jugs. It’s less waste, and there’s less leaky gallons than [previously]. Costco was constantly complaining about leaky gallons/bad boxes, so this was the solution.”
Are these boxy jugs being phased out?
While there have been rumbling about phasing out the square milk jugs, Le doesn’t think this will actually happen—at least not anytime soon. “Given that consumers who shop at Costco do so primarily for cost savings and not aesthetic appeal, as evidenced by the fact that Costco is still popular despite the minimalistic warehouse structures they occupy, it’s unlikely that Costco will change its packaging,” Le says.
He goes on to note that the square packaging for milk jugs has been adopted by other club membership retailers, like Sam’s Club, where, again, price is a major factor for customers.
Plus, as some Redditors note, even though these jugs may seem weird at first, you’ll likely get used to them in no time. And now that you know cost is a huge factor here, we’re guessing you’ll look a lot more kindly on them.
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Sources:
- John Anthony, owner of Andex; interviewed, July 2025
- Bryan Quoc Le, PhD, food scientist, founder of Mendocino Food Consulting and author of 150 Food Science Questions Answered; interviewed, July 2025
- Reddit: “The 1-gallon milk jug is not as easy to pour from like the standard ones”
- Reddit: “Costco Milk Packaging, I Hate You So Much”
