Inc. added six million Prime members in the back half of 2018, according Consumer Intelligence Research Partners estimates, and membership growth is slowing. Inc. had 101 million members of its Prime loyalty program in the United States as of December, according to new estimates from Consumer Intelligence Research Partners (CIRP).

The retail giant added 6 million U.S. consumers to Amazon Prime in the second half of 2018, with two-thirds of those new signups joining in the fourth quarter, CIRP estimates.

Amazon does not disclose how many Prime members it has by country; however, in 2018 it said it had more than 100 million globally.

CIRP’s membership estimates are based on the results of an online survey of 500 online shoppers. CIRP says that with 101 million members in the U.S., 62% of Amazon’s customers in the U.S. are Prime members. There are approximately 126 million households in the United States, per the U.S. Census Bureau. As many Prime customers share their memberships with their households, Amazon Prime’s reach may be much longer. Using CIRP’s 101 million figure and the Census figure, Prime may be a part of 80% of U.S. households. (This does not take into account households that may have multiple individual Prime accounts.)


Amazon raised the price of a Prime membership in the United States to $119 in May 2018, up from $99. In March it began offering Prime membership benefits to consumers who are part of Medicaid, the public health program for low-income Americans, for $5.99 a month, expanding on a program launched in 2017 to offer Prime memberships at a discounted price to consumers who receive government assistance.

Prime members are important to Amazon because Prime customers shop more often and spend more money with Amazon than Amazon customers who are not Prime members. Prime members spend an average of $1,400 annually on Amazon, whereas customers who are not a part of Prime spend about $600. CIRP data from 2018 says Prime customers place an average of 24 orders per year with Amazon, while non-Prime Amazon customers place about 13.

Given the large base of consumers who are already part of Prime, the growth rate for new signups among U.S. consumers is slowing, growing 10% year over year.

Amazon is No. 1 in the Internet Retailer 2018 Top 1000.