Christianity was the largest religion in the world in Pew Research Center’s 2020 estimates, published in 2025. About 2.3 billion people identified as Christian, or 28.8% of the world’s population. Islam was next, with about 2 billion people, or 25.6%. The Christian figure brings together many churches and traditions. The way those groups are combined helps explain what a global ranking can tell us and what becomes visible when a national census reports religious affiliation in more detail. Pew Research Center’s worldwide 2020 estimates Pew Research Center’s methodology
Who is included in the count?
For its world comparison, Pew combines Christian traditions into one category. A Roman Catholic, an Eastern Orthodox Christian and a Protestant can all contribute to that total while belonging to different churches. The estimate also includes people whose degree of religious involvement varies. The underlying sources include censuses, surveys and population registers, and they vary by country. The global figure is an estimate of affiliation across those sources. It answers a question about religious identity, while questions about attendance or belief require other measures. Pew Research Center’s worldwide 2020 estimates Pew Research Center’s methodology
Grouping also affects how changes are counted. In a global table with a single Christian category, a person raised Catholic who later identifies as Protestant remains in the Christian category. In a study designed to track changes among Christian traditions, the same response counts as a switch. Pew’s U.S. Religious Landscape Study makes that distinction by recording movement across broad religious categories as well as some movement within Christianity. The two approaches capture changes at different levels of detail. Pew Research Center’s methodology Pew Research Center’s U.S. Religious Landscape Study
Where the world’s Christians lived in 2020
Sub-Saharan Africa accounted for about 31% of the world’s Christians in 2020, compared with about 22% in Europe. The two regions had changed places since 2010. Pew connects the shift to more rapid population growth in sub-Saharan Africa and to people leaving Christian affiliation in parts of Europe. The regional shares describe where Christians lived. They are distinct from the percentage of residents within each region who identified as Christian. In sub-Saharan Africa the Christian count rose by 31% to about 697 million, while the Christian share of local residents increased by less than one percentage point to 62%. The large increase in the count accompanied an increase in the region’s overall population. Europe’s Christian count fell by 9% to about 505 million. Pew Research Center’s worldwide 2020 estimates Pew Research Center’s Christian population chapter
The world’s Christian population is spread across many countries. In Pew’s comparison of geographic concentration, it takes at least twelve countries, starting with the largest Christian populations, to reach just over half the worldwide Christian total. That means the 2.3 billion figure cannot be read as the result of religious trends in just one or two countries. A trend in one country can run in a different direction from the global count. For instance, the United States still had the largest national Christian population in 2020, even though the share of its residents identifying as Christian had fallen from 78.3% in 2010 to 64.0% in 2020. About one in ten of the world’s Christians lived in the United States that year. Pew Research Center’s worldwide 2020 estimates Pew Research Center’s Christian population chapter Pew Research Center on geographic concentration
What the Brazilian census adds
Brazil’s statistics agency, IBGE, gives a more detailed view of change within Christianity. In its preliminary 2022 census sample estimates for residents aged ten and older, 56.7% identified as Roman Catholic and 26.9% as evangélico, a census category commonly translated as Protestant or evangelical. In the comparison for the same age range in 2010, the corresponding shares were 65.0% and 21.7%. The categories moved in different directions over the period. The global category alone would not show how the balance between them changed. IBGE presentation on religious affiliation in Brazil
Those Brazilian percentages refer to a particular country and age range, and the final year is 2022. Pew’s global estimates use 2020 and cover people of all ages. Comparing the sources is useful because they answer different questions. The Brazilian figures show the relative sizes of particular affiliations among residents in the census age range. The Pew estimates allow a worldwide comparison among broad categories. Pew Research Center’s worldwide 2020 estimates Pew Research Center’s methodology IBGE presentation on religious affiliation in Brazil
How the largest group can lose share
Pew estimates that the Christian population grew by about 122 million between 2010 and 2020. The world’s total population grew faster, so the Christian share declined by 1.8 percentage points even as the count rose. Islam grew more quickly over the same interval while still having fewer adherents in 2020. A ranking by total size compares how many people were counted at one point. A ranking by growth compares how much the count changed during a period. Pew Research Center’s worldwide 2020 estimates Which major religion grew fastest from 2010 to 2020?
Conclusion
Christianity leads the worldwide affiliation estimates for 2020 when its traditions are counted together. The breakdown by region shows how the center of population shifted between Europe and sub-Saharan Africa. Brazil’s census shows a different kind of change within Christianity itself. The global total, the regional distribution and the national breakdown each answer a different question about the same broad religious category. Pew Research Center’s worldwide 2020 estimates Pew Research Center’s Christian population chapter IBGE presentation on religious affiliation in Brazil
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