Walmart vs. Costco: A Grocery Price Test That May Change How You Shop

Grocery prices can feel unpredictable, even when you shop at the same stores. Many people assume they already know which retailer is cheaper. But when one shopper put that assumption to the test, the results told a more complicated story.

The Test That Started It

Instead of guessing, one journalist decided to test it. Business Insider’s Savannah Born took the same grocery list of 32 common items and brought it to both Walmart and Costco. She compared prices carefully, breaking them down by cost per ounce or pound to keep things fair. It was not just a quick glance. It was a full comparison.

What She Expected vs Reality

Like many shoppers, Born assumed Walmart would come out cheaper. The store’s branding, discounts, and smaller package sizes make it feel like the more affordable option. But once she started comparing unit prices, the results surprised her. The difference was not small.

Costco Comes Out Ahead

Across the full list, Costco delivered lower prices overall. Born found that her total grocery haul would cost about 25 to 26 percent less at Costco when comparing equivalent quantities. That finding lines up with broader research showing similar gaps in pricing.

Where Costco Really Wins

The biggest savings showed up in bulk-friendly categories. Items like cheese, butter, snacks, cereal, and pantry staples were consistently cheaper per ounce at Costco. For example, cheese was priced around $2.60 per pound at Costco compared to $3.46 at Walmart. Over time, those differences add up.

Where Walmart Still Competes

Walmart did not lose across the board. Some everyday essentials like eggs, chicken, flour, and sugar were actually cheaper at Walmart, especially when comparing smaller quantities. For shoppers who only need a few items, those differences can still matter.

Size and Flexibility Matter

One of the biggest differences is how each store sells its products. Costco focuses on bulk, which lowers the price per unit but requires buying more upfront. Walmart offers smaller portions, giving shoppers more flexibility even if the cost per ounce is higher. That trade-off changes how people experience “value.”

The Membership Factor

Costco’s pricing comes with a condition. Shoppers need to pay an annual membership fee, typically around $65. Whether the savings outweigh that cost depends on how often someone shops and how much they buy. For frequent shoppers, the math can work. For others, it may not.

Not Just About Price

Price is only part of the story. Born also noted differences in quality, variety, and convenience. Costco often delivered better consistency in produce and bulk items, while Walmart offered more variety and easier access without a membership. Choosing between them is not always straightforward.

What This Means for Shoppers

This comparison does not point to a single “winner” for everyone. Costco may offer lower prices overall, especially for bulk purchases, but Walmart still makes sense for smaller households, quick trips, or specific items. In the end, the biggest takeaway may be this: saving money on groceries is not just about where you shop, but how you shop.