Costco ecommerce rose in both the retailer’s fiscal Q4 and full-year 2026 at more than double the rate of total comparable sales, with the retailer crediting third-party delivery for online orders.
Along with ecommerce, gas and pharmacy sales growth outpaced core merchandise during Costco’s fiscal Q4, which ended Aug. 30. Total Costco sales in Q4 increased 9.4%, whereas they grew 8.4% for the full fiscal 2026.
Overall, Costco revenue in Q4 reached $95.72 billion. That marked 11.1% year-over-year growth from about $86.16 billion. Sales accounted for 98% of Costco revenue in Q4, with membership fees comprising the remainder. Costco net sales in Q4 increased about 11.2%, to $93.87 billion, from $84.43 billion.
For its full-year 2026, Costco net sales rose 10.1%, to about $297.25 billion, from $269.91 billion. Meanwhile, Costco revenue in 2026 increased at about the same rate, to $303.15 billion from $275.26 billion.
Costco is No. 6 in the Top 1000 Database. The market research tool tracks North America’s largest online retailers, ranking them by annual ecommerce sales and more.
Costco is also No. 558 in Digital Commerce 360’s new AI Rankings. That set of rankings is available in the Top 1000 Pro with AI Database.
Costco ecommerce sales in Q4 2026
In its fiscal Q4 2026, Costco ecommerce sales increased 19.5% year over year. That growth came as Costco ecommerce sales rose 20.9% for its full fiscal 2026.
For the full fiscal year, Costco digital sales exceeded $33 billion. In that figure, CEO Ron Vachris included sales through third-party delivery platforms.
And in the weeks leading up to Costco’s Q4 earnings call, the retailer expanded its last-mile delivery partnerships. Costco expanded its Uber Eats partnership from 17 states to nationwide. Additionally, Costco expanded its DoorDash partnership to include the U.S.
Vachris noted that Costco members using the marketplaces “are significantly younger” than its overall base. Average delivery times across Instacart, DoorDash and Uber Eats are also less than an hour, he added.
Chief financial officer Gary Millerchip said as younger members engage with Costco, “they’re generally signing up through a digital phone or laptop or iPad because that’s the way they generally start that engagement and journey.”
What it has found, he said, is that how Costco communicates with those members “definitely requires continued growth in our digital capabilities through improving the member experience online and through the app.”
Part of that improved customer experience has come from using the information the retailer has on its customers to provide more personalized experiences. Millerchip said Costco saw triple-digit growth in sales from personalized initiatives in Q4. He noted that 10% of all Costco.com orders now include a personalized item.
Additionally, Vachris noted that Costco’s number of members under the age of 40 has increased about 60% since the start of the COVID-19 pandemic in 2020. They now account for more than a quarter of all members.
Impact of AI on Costco site and app traffic in Q4
Total Costco website and app traffic increased 30% year over year in Q4.
The categories that drove the most digital sales at Costco were:
- Domestics
- Hardware
- Health and beauty
- Home furnishings
- Housewares
- Pharmacy
- Small electrics
The retailer has also discontinued Costco Next.
“As our digital capabilities mature, we believe that integrating the most popular items and brands from Costco Next more seamlessly into the Costco app and website provides a better member experience and will increase sales,” Millerchip said.
And while starting from a low base relative to other channels, artificial intelligence (AI) continues to have a growing influence on how Costco members search for products, according to Millerchip. Traffic to Costco’s website from AI search also saw triple-digit growth during Q4, the second straight quarter to see such an increase.
“We don’t do any paid digital advertising,” Millerchip said. “We certainly appear in digital advertising more because of the sort of reputation that we have and as our members talk about us on social media, but AI presents an opportunity in a sort of a neutral environment for us to be able to ensure that our value and our quality shows up transparently for our members.”
Additionally, AI referrals have the highest conversion rate of all traffic to Costco’s website. Millerchip said similar to ecommerce sales overall, appliances and consumer electronics led sales originating from AI search.
“Interestingly, the Costco membership is also among the top items originated from AI searches, indicating that there is a strong positive sentiment around the value of our membership coming from these sources,” Millerchip said.
How many members did Costco have in Q3?
Costco ended its Q3 with 84.1 million paid household members. That’s 3.8% year over year. It’s also an increase from 82.9 million in Q3.
Of those, 42.3 million had paid executive memberships — 9.4% more than the prior-year period.
Costco also ended Q4 with 150.4 million cardholders, a 3.6% year-over-year increase. That’s also up from 148.5 million cardholders in Q3.
In Q4, Costco generated about $1.85 billion in membership fee income. That’s 7.3% year-over-year growth, or $125 million more than last year. At the end of Q4, Costco’s U.S. and Canada membership renewal rate was 92.3%. Worldwide, it was 89.8%.
How many countries have a Costco?
As of the end of its fiscal Q4 2026, Costco operates 939 warehouses. Of those, 647 are in the United States and Puerto Rico. Listed by warehouse count, the rest are in:
- Canada (115)
- Mexico (43)
- Japan (37)
- The United Kingdom (29)
- South Korea (20)
- Australia (15)
- Taiwan (14)
- China (7)
- Spain (5)
- France (3)
- Sweden (2)
- Iceland (1)
- New Zealand (1)
Costco operates ecommerce sites in:
- Australia
- Canada
- China
- Japan
- Mexico
- South Korea
- Taiwan
- The United States
- The United Kingdom
Percentage changes may not align exactly with dollar figures due to rounding. Check back for more earnings reports. Here’s last quarter’s update on Costco ecommerce sales.
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