Major Religious Groups in the World – 1945/2023

In 2023, how many people believe in a Religion? And which Religion do they believe in? What are the most popular religions in the world? Various data on religions around the world are analyzed in the article. Worldwide more than 85 percent of the population believes in a religious group. Worldwide there are an estimated 4,200+ religions.

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 2023 (approx.):

  1. Islam Summy: 1,543,271,481;
  2. Christian Roman Catholic: 1,250,319,000;
  3. Hindu: 1,073,619,000;
  4. Christian Protestants: 624,924,000;
  5. Buddhism Mahayana: 334,718,996;
  6. Christian Eastern Orthodox: 293,599,000;
  7. Islam Shia: 215,232,293;
  8. Buddhism Theravada: 185,328,289;
  9. Shinto: 121,818,711;
  10. Christian Anglican: 75,331,423;

But how does the ranking change when analyzing the data of more specific religions? In first position among the world’s most professed religions is Sunni Islam. In fact, the Sunni population is par to over 1.5 billion and is almost 300,000 more than the Roman Catholic Christian religion, which is just over 1.250 billion people worldwide. In third position among the most practiced religions is Hindu cin 1.073 billion people and followed in fourth position by the Protestant religion which is practiced by nearly 600 million people worldwide. If we add to the figure of Roman Catholics and Protestants that of the Orthodox, who number just under 300,000, that is why Christianity as a whole is the number one religion worldwide.

Most Popular Religion in USA

The most popular religion in the U.S. is Christianity, comprising the majority of the population (73.7% of adults in 2016). The majority of American Christians belong to a Protestant denomination or a Protestant offshoot, such as Mormonism or the Jehovah’s Witnesses. According to the Association of Statisticians of American Religious Bodies newsletter published in March 2017, utilizing data from 2010, Christians held the largest religious presence in all 3,143 counties in the country. Roughly 48.9% of Americans identify as Protestants, while 23.0% adhere to Catholicism, and 1.8% align with Mormonism (members of the Church of Jesus Christ of Latter-day Saints). The roots of Christianity in the United States trace back to the period of European colonization, when various Christian denominations established their presence on the continent. Notably, the United States is home to the world’s largest Christian population, reflecting the diverse array of Christian traditions that have taken root and flourished over centuries.

Plurality of religious preference by state in U.S. (2014).

Data published by the Pew Center Research highlights a notable decline in the percentage of Protestant Christians in the United States over time. In the early 20th century, specifically in 1900, the proportion of individuals identifying as Christian-Protestant was nearly 90 percent, underscoring the religion’s widespread influence at that time. Catholicism represented the second-largest religious group, comprising slightly over 10 percent of the population, while all other religious affiliations, including non-believers, constituted only small fractions. However, the subsequent years witnessed a substantial decrease in the percentage of Protestant Christians, plummeting to below 50 percent by 2010. In a contrasting trend, the demographic of unaffiliated individuals has experienced a significant surge. Initially constituting less than 1 percent of the population in 1900, the unaffiliated category has burgeoned to encompass almost one-third of the total U.S. population today, exemplifying the evolving religious landscape of the nation.

Most Popular Religion in 2050

The growth of Islam also due to the increase in population in some parts of the world has been very fast. So has the rise of the Hindi Religion. But what will be the most practiced religions in 2050 and 2100? The Pew Researcher Center has tried to answer this question with a research. According to this study in 2050 the first religion (by group) will still be Christian. Compared to 2.17 billion in 2010, the population will increase to 2.92 billion. A strong growth, but that will be less than strong Muslim population. In fact this will pass from 1.6 billion to 2.76 billion. In 2050 Christians and Muslims will be more or less equal in terms of population in the world.


While increasing in absolute terms, the Christian population in percentage terms will not change from 2010 to 2050. In fact, if in 2010 it was 31.4% of the total population, in 2050 it will remain 31.4%. Growing, however, will be the Muslim population. From 23.2% in 2010 it will rise to 29.7%. Almost 3/10 of the population will profess this religion in 2050.

Oldest religion in the World

Christianity is in 2022 the most widespread religion worldwide. But what are the oldest religions in the word? Answering this question is by no means simple. In fact, most of them were born before the invention of written history about 5,000 years ago. According to several sources, the oldest religion in the world is Hinduism. Born over 4,000 years ago, Hinduism is still one of the most important religions around the world. The history of Hinduism holds together several religious traditions that developed especially in the sub-Indian continent. The combination of these cultures and traditions makes it the oldest religion in the whole world.

In second place of the oldest religions worldwide is Judaism. The Abrahamic religion turns out to be the oldest monotheistic religion worldwide. Its origin-again according to the estimates of historians and religious people-was in the Kingdom of Israel. Among the oldest religions we find in third position Zoroastrianism. Zoroastrianism which is based on the belief of the prophet Zarathustra was for many years one of the most widespread religions in the Central Asian area. This is also a monotheistic religion.

Sources and links helpful in writing the article

To explore some data on the future of religions to 2100 I recommend reading this article/research. The most popular religions up to the new century are shown:

To see the video on the evolution of Religions from 1945 to 2020:

To read more articles:

Other interesting data