E-commerce giant Amazon is ramping up its same-day delivery service, a lucrative part of its business, with just how many facilities that will involve now becoming clear.

CEO Andy Jassy announced plans on Amazon's most recent earnings call to double the number of same-day fulfillment centers the company operates. While Amazon hasn't made clear how many of these types of facilities it has, a new CoStar analysis identified 51 of them across the U.S. totaling just over 8M SF.

The vast majority of those buildings, roughly 80%, are in properties built since 2015, and 90% are between 100K SF and 250K SF, according to the analysis. While many of Amazon's larger fulfillment centers are build-to-suit buildings where it is the only tenant, 40% of the buildings where Amazon leases same-day centers have other tenants.

The same-day delivery centers have an average of 33-foot ceiling heights, above the average of 26 feet for similarly sized industrial buildings across the country, according to CoStar.

The expansion of the same-day network is somewhat of a reversal for Amazon, which last year canceled, closed or delayed scores of warehouses across the country in its quest to cut costs after aggressively expanding in the early days of the pandemic. By one analysis, the retreat affected 30M SF of operational or planned space in 2022.

As of March this year, the firm was still planning to open another 231 facilities comprising more than 82M SF. More than half of those buildings are slated to be delivery centers, Supply Chain Dive reported at the time.