In 2025, how many people believe in a religion? And which religions do they adhere to? What are the most popular religions globally? It is estimated that more than 85 percent of the global population identifies with a religious group. There are approximately 4,200+ religions worldwide.
Most popular religions in the world
Out of Earth’s 8 billion inhabitants, it is estimated that about 2.6 billion people believe in Christianity. The figure of 2.6 billion believers takes into account several denominations including Catholicism, Protestantism, the Orthodox Church and other various smaller groups. In total, Christians represent 31.7 percent of the world’s population. In second position among the world’s most popular religions in 2023 is Islam, which accounts for nearly 25 percent of the total population. And in third position is Hinduism which has nearly 1.2 billion adherents and about 15 percent of the total population.
Most popular religions in the world 2025 (approx.):
Islam Sunni: 1,579,268,274;
Christian Roman Catholic: 1,268,004,246;
Hindu: 1,075,098,000;
Christian Protestants: 625,452,306;
Buddhism Mahayana: 341,318,714;
Christian Eastern Orthodox: 294,957,346;
Islam Shia: 221,790,956;
Buddhism Theravada: 187,979,425;
Shinto: 122,667,219;
Christian Anglican: 75,844,450;
But how does the ranking change when analyzing the data of more specific religions? Sunni Islam remains the world’s most professed religion. In fact, the Sunni population now stands at over 1.579 billion, which is nearly 300,000 more than the Roman Catholic Christian religion, now totaling about 1.268 billion people worldwide. Hinduism holds the third position among the most practiced religions with approximately 1.075 billion adherents. Following in fourth position is Protestant Christianity, practiced by about 625 million people worldwide. Adding the figures of Roman Catholics, Protestants, and the Eastern Orthodox, who number nearly 295 million, Christianity as a whole remains the number one religion globally.
Most Popular Religion in USA (2025)
Christianity remains the most prevalent religion in the U.S. as of 2023, though its share among the population has been gradually declining. Approximately 67% of Americans still identify as Christian, down from previous years. This group includes a wide array of denominations with varying levels of adherence. Within Christianity, the demographic has become more racially and ethnically diverse over the years. White Christians now make up 41% of the population, a noticeable decrease from past figures. Meanwhile, Christians of color have maintained a steady presence, representing about 25% of the American Christian population.
The landscape of American religion is changing, with notable shifts in affiliation and demographic composition. Non-Christian religions maintain a relatively small portion of the U.S. population, around 5%, with figures remaining steady across groups such as Jewish (1.9%), Muslim (0.9%), Buddhist (0.7%), and Hindu (0.7%) Americans.
The “religiously unaffiliated,” often referred to as “nones,” are on the rise, now representing 27% of the population. This increase reflects a broader trend of growing secularism and diversity in American religious life. Disaffiliation is occurring across all age groups, not just among the youth, indicating a significant cultural shift towards secular values or alternative spiritual frameworks.
Urban areas, in particular, display high religious diversity, whereas rural regions and the Deep South tend to have less variation in religious affiliation. Additionally, political affiliation correlates with religious identity, with Republicans more likely to be white and Christian compared to Democrats, who show greater religious diversity and a higher proportion of religiously unaffiliated members.
These trends are essential for understanding the evolving religious landscape in the U.S., reflecting broader social changes and shifts in individual and collective beliefs and practices. For more detailed analysis and data, you can explore resources from the Pew Research Center and PRRI, which provide extensive surveys and reports on these topics.
Research by the Pew Research Center has documented a notable decline in Protestant Christianity in the United States over the years. In the early 20th century, nearly 90% of Americans identified as Protestant Christians, emphasizing the profound influence of this religious tradition at the time. Catholicism was the second largest group, making up just over 10% of the population, while all other religious affiliations constituted smaller fractions.
However, the landscape of American religiosity has significantly transformed since then. By 2014, the proportion of Americans identifying as Protestant Christians had decreased to 46.5%, and this downward trend has continued into more recent years. As of the latest findings, Protestants no longer constitute the majority of U.S. adults. This shift is closely tied to the rise of religiously unaffiliated individuals, often referred to as “nones,” whose numbers have grown from 16% in 2007 to 23% in 2014 and continue to increase. These “nones” include atheists, agnostics, and those who subscribe to “nothing in particular.”
The decline in Protestant Christianity is mirrored by a broader decrease in Christian affiliation overall, which has not only dropped in relative share but also in absolute numbers. Between 2007 and 2014, the U.S. saw a reduction of approximately 5 million Christians, despite the population increase during that period.
These changes reflect broader societal shifts, including generational changes in religious affiliation and a growing propensity across all age groups to move away from organized religion. The rise of the religiously unaffiliated highlights a significant cultural shift towards more secular values and diversified spiritual orientations in the United States.
[ source: statisticsanddata.org ]