The U.S. remains a religious nation, with more than seven in 10 affiliating with some type of organized religion. However, far fewer, now less than half, have a formal membership with a specific house of worship. 

WASHINGTON, D.C. — Americans’ membership in houses of worship continued to decline last year, dropping below 50% for the first time in Gallup’s eight-decade trend. In 2020, 47% of Americans said they belonged to a church, synagogue or mosque, down from 50% in 2018 and 70% in 1999.

As many Americans celebrate Easter and Passover this week, Gallup updates a 2019 analysis that examined the decline in church membership over the past 20 years.

Gallup asks Americans a battery of questions on their religious attitudes and practices twice each year. The following analysis of declines in church membership relies on three-year aggregates from 1998-2000 (when church membership averaged 69%), 2008-2010 (62%), and 2018-2020 (49%). The aggregates allow for reliable estimates by subgroup, with each three-year period consisting of data from more than 6,000 U.S. adults.

Decline in Membership Tied to Increase in Lack of Religious Affiliation

The decline in church membership is primarily a function of the increasing number of Americans who express no religious preference. Over the past two decades, the percentage of Americans who do not identify with any religion has grown from 8% in 1998-2000 to 13% in 2008-2010 and 21% over the past three years.

As would be expected, Americans without a religious preference are highly unlikely to belong to a church, synagogue or mosque, although a small proportion — 4% in the 2018-2020 data — say they do. That figure is down from 10% between 1998 and 2000.

Given the nearly perfect alignment between not having a religious preference and not belonging to a church, the 13-percentage-point increase in no religious affiliation since 1998-2000 appears to account for more than half of the 20-point decline in church membership over the same time.

Most of the rest of the drop can be attributed to a decline in formal church membership among Americans who do have a religious preference. Between 1998 and 2000, an average of 73% of religious Americans belonged to a church, synagogue or mosque. Over the past three years, the average has fallen to 60%.

Generational Differences Linked to Change in Church Membership

Church membership is strongly correlated with age, as 66% of traditionalists — U.S. adults born before 1946 — belong to a church, compared with 58% of baby boomers, 50% of those in Generation X and 36% of millennials. The limited data Gallup has on church membership among the portion of Generation Z that has reached adulthood are so far showing church membership rates similar to those for millennials.

The decline in church membership, then, appears largely tied to population change, with those in older generations who were likely to be church members being replaced in the U.S. adult population with people in younger generations who are less likely to belong. The change has become increasingly apparent in recent decades because millennials and Gen Z are further apart from traditionalists in their church membership rates (about 30 points lower) than baby boomers and Generation X are (eight and 16 points, respectively). Also, each year the younger generations are making up an increasingly larger part of the entire U.S. adult population.

Still, population replacement doesn’t fully explain the decline in church membership, as adults in the older generations have shown roughly double-digit decreases from two decades ago. Church membership is down even more, 15 points, in the past decade among millennials.

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