Amazon's Project Mercury would put a same-day warehouse within 10 miles of 80% of Prime members

The distance between roughly 85 same-day facilities and the 1,000 in the plan is about 915 buildings ^[19]. Amazon's own capital estimate for an Orbital site, the smaller format it hopes will speed the expansion, is about $48.4 million ^[18][23]. Multiply that by 915 and the number lands near $44 billion, before inventory and labour ^[20]. Not every new site would be an Orbital, and Business Insider puts the cost at billions of dollars without a total ^[2].

Then there is the schedule. Business Insider published the documents in September 2026, which leaves about five years to the 2031 date ^[22]. Averaged across that window, openings would run near 183 a year, and each one needs a site, a permit and a workforce ^[21].

The coverage numbers do not sit on the same base. Amazon's target counts 80% of US Prime subscribers inside a 10-mile straight-line radius ^[6]. Walmart's figure counts about 90% of the US population within 10 miles of a Walmart or Sam's Club, and Walmart says 95% of US households can already receive delivery in under three hours ^[11][12]. One denominator is a subscriber list, the other is the country. Read on Amazon's own document, the 2031 finish line sits behind where Walmart says it stands now.

A skeptic would say internal planning documents are not commitments, and Amazon's spokesperson said close to that. The projections are "preliminary, subject to significant revision, and shouldn't be treated as finalized plans," the spokesperson told Business Insider ^[7]. The spokesperson also said: "That said, it's no secret that we're focused on delivering faster for customers and the expansion of our same-day delivery network is playing a big role in that" ^[9]. Amazon adds that its same-day network already serves more than 10,000 cities and towns, and that same-day orders are not filled only through SSD facilities ^[8].

Proximity matters most in the category Amazon is chasing. Amazon says its grocery business generates more than $150 billion in annual gross sales, a figure that includes nonperishable products, and Business Insider reports Walmart's grocery business is much bigger ^[16]. In Canada, an internal planning document said major retailers were "outpacing our delivery capabilities," citing investments by Walmart and Best Buy ^[15].

Density is one route among several Amazon is running at once. Business Insider has previously reported Project Kobe, a plan for Walmart-sized stores with large automated backrooms that would fulfil online orders and work as local delivery hubs ^[13]. Amazon is also testing an all-day model with 10 overlapping delivery windows, expanding its Amazon Now ultrafast service, and using SSDs as launch points for Prime Air drones ^[14].