Since the dawn of humanity, people have sought to understand our existence and the world around us. This quest for meaning has given rise to diverse systems of beliefs and practices that we recognize as religions. Émile Durkheim, a foundational figure in sociology, highlighted religion as a fundamental social institution that consistently shapes social life. Throughout history, population growth has been closely linked with the expansion of religious life. Today, approximately 85 percent of the global population identifies with a specific religious belief. But when we ask “How Many Religions Are There?”, the answer is more complex than a simple number.
While estimates suggest there are around 10,000 distinct religions in the world, this number can be fluid depending on how “religion” is defined and categorized. However, a significant majority of the global population, over three-quarters, adheres to one of the four largest religious traditions. Let’s delve into the demographics of these major faiths and explore the landscape of global religious diversity.
The Four Pillars: Largest Religions Worldwide
Christianity, Islam, Hinduism, and Buddhism stand as the four largest religions globally, collectively encompassing over 75% of the world’s religious population.
Christianity: A Global Faith
Originating in the Middle East nearly 2,000 years ago, Christianity has grown to become the world’s largest religion, with approximately 2.4 billion followers. It is the dominant religion across the Americas, Europe, Oceania, and sub-Saharan Africa. Within Christianity, diverse denominations exist, with roughly half identifying as Catholic, 37 percent as Protestant, 12 percent as Orthodox, and 1 percent as “Other” Christian traditions. Notably, the United States holds the largest Christian population globally (11.3% of the world total), followed by Brazil (8%) and Mexico (5%).
Islam: Diversity and Global Reach
Founded in 622 CE, Islam is the second-largest religion, with nearly 2 billion followers worldwide. The majority of Muslims belong to the two major branches, Sunni and Shia. Islam’s followers, known as Muslims, represent a vast array of ethnic backgrounds and languages and constitute the majority population in 49 countries, primarily across the Middle East, North Africa, and parts of South Asia. Indonesia has the largest Muslim population (13.1% of the world total), followed by India (11%), Pakistan (10.5%), and Bangladesh (8.4%). Karachi, Pakistan, boasts the largest Muslim city population globally.
Hinduism: Ancient Roots in India
Hinduism, with origins dating back to Northern India around 2000 BCE, is one of the oldest religions in the world. Today, the vast majority of its 1.2 billion adherents reside in India and Nepal.
Buddhism: From India to Asia and Beyond
Buddhism, also originating in ancient India in the 5th century CE, has spread across Asia and the world. Countries with significant Buddhist populations include Mongolia, Thailand, Myanmar, Laos, and Cambodia. China is home to approximately half of the world’s 500 million Buddhists.
Beyond the Big Four: Smaller Religious Communities
While the four largest religions dominate, around 7 percent of the global population identifies with numerous religions with smaller followings.
Judaism, although a major Abrahamic religion alongside Christianity and Islam, accounts for a smaller percentage globally, representing just 0.2 percent of the world’s population (approximately 16 million people). The majority of Jewish people live in Israel (7 million) and the United States (6 million). Historical events, such as the Holocaust, significantly impacted Jewish population numbers, and it’s estimated that without these tragedies, the Jewish population could be twice its current size.
An estimated 6 percent of the world’s population adheres to folk or traditional religions. This diverse category includes African traditional religions, Chinese folk religions, Native American religions, and Australian aboriginal religions, among others.
Another 1 percent of the global population follows a variety of other faiths, including Baha’i, Taoism, Jainism, Shintoism, Sikhism, Tenrikyo, Zoroastrianism, Wicca, and many more. This demonstrates the vast spectrum of religious expression across the globe.
The Rise of the Non-Religious
It’s important to acknowledge the significant portion of the global population, approximately 16 percent, who identify as non-religious. This group, often referred to as “nones,” includes atheists, agnostics, and individuals who may hold spiritual beliefs but do not affiliate with any particular religion. Countries with substantial non-religious populations include China, Japan, and the United States. In the U.S., the percentage of “nones” has significantly increased from 8 percent in 2000 to 21 percent in 2022, indicating a growing trend in secularization in some regions. In several countries like China, Japan, South Korea, North Korea, Czechia, and Estonia, non-religious populations are in the majority.
Religion, Fertility, and Future Trends
Pew Research indicates that regions with higher levels of religiosity are experiencing faster population growth, primarily due to higher fertility rates and younger populations. Niger, for example, with the world’s fastest-growing population (3.7% annually) and highest fertility rate (6.8 children per woman), is projected to quadruple in population by 2070. Notably, a large majority (86%) of adults in Niger consider religion very important in their lives. Conversely, Japan, with a shrinking population (-0.5% annually), has a low percentage of religiously affiliated individuals (10%). Japan’s population is expected to decline by 28 percent in the next 50 years.
Muslim populations exhibited the highest fertility rate among major religious groups studied by Pew (2.9 in 2015-2020). The median age for Muslims during this period was 23, with a significant proportion (34%) in the youngest age bracket (0-14 years). This contrasts with a median age of 28 and 27 percent in the 0-14 age group for the global population overall. However, it’s crucial to note that fertility rates within Muslim-majority countries, like all regions, are influenced by factors like women’s education. Higher educational attainment for women is correlated with lower fertility rates, even in Muslim-majority contexts.
Christian populations also continue to grow, with a fertility rate higher than the global average (2.6 in 2015-2020 compared to the world average of 2.4). Approximately 33 percent of global births in recent years were to Christian parents, slightly exceeding Christianity’s share of the world population (31% in 2015). Fertility rates among Christians vary geographically, being lowest in Europe (1.6) and highest in sub-Saharan Africa (4.4).
Fertility rates for Hindus (2.3) and Buddhists (1.6) are lower than those of Christians and Muslims globally. The non-religious population exhibits a considerably lower completed family size (1.6) compared to the world average.
Globally, fertility rates are declining across all major religious groups, with projections suggesting a convergence towards the replacement level (2.1) later this century. This trend is influenced by factors such as increased access to contraception, improved education and status for women, better healthcare, and economic growth. Historically, most world religions promoted pro-fertility norms, reflecting high infant mortality and lower life expectancy. However, as child survival and longevity improved in the 20th century, societal views on gender and sexuality, and consequently family size, began to evolve within different faith communities.
Religion and Governance
Religion’s influence extends beyond personal beliefs, often shaping national governance. Over 20% of countries (43) have official state religions.
Islam holds the status of official religion in 27 countries across Asia, sub-Saharan Africa, North Africa, and the Middle East. Among these, eight identify as “Islamic states,” incorporating Islam as the foundational ideology of their state and constitution (Afghanistan, Brunei, Iran, Mauritania, Oman, Pakistan, Saudi Arabia, and Yemen).
Several countries recognize Christianity as their state religion, often identifying as Christian republics. These include Argentina, Costa Rica, Finland, Greece, Armenia, Samoa, Iceland, and Malta. Buddhism is the state religion in Bhutan and Cambodia, while Israel is officially recognized as a Jewish state. No country has Hinduism as its state religion.
Conversely, in 10 countries, particularly those with a history of Communism, the state exhibits hostility towards religion or tightly regulates religious institutions. These include China, Cuba, North Korea, Vietnam, and several former Soviet republics.
The Evolving Religious Landscape
While the “nones” are growing in some regions like the United States, this is not a global trend. Globally, the proportion of non-religious individuals is projected to decrease from 16 to 13 percent by 2060. This is largely due to population growth being concentrated in more religious regions. A survey across 26 countries by Ipsos Global Advisor revealed a higher prevalence of religious affiliation and practice in the Global South, with more secular populations in the Global North. Population shifts and demographic changes, driven by birth rates, migration, and religious conversion, will continue to reshape the global religious landscape.
Both Muslim and Christian populations are projected to grow in the coming decades. By later in the 21st century, Islam is expected to become the largest religious group globally. Pakistan is anticipated to surpass Indonesia as the country with the largest Muslim population. Sub-Saharan Africa, the world’s fastest-growing region, will see the most significant growth in Islam, with Nigeria potentially hosting more Muslims than Egypt later this century.
Christianity is also projected to experience substantial growth, particularly in Africa, where an 85 percent increase is expected within the next 30 years. By 2050, it’s estimated that 4 out of 10 Christians globally will reside in sub-Saharan Africa. Evangelical and Pentecostal denominations are experiencing the most rapid growth within Christianity. Pentecostalism, a movement emphasizing personal spiritual experiences and charismatic gifts, could account for approximately one-third of the 3.3 billion Christians by 2050.
Hindu and Buddhist populations are expected to experience more modest growth in the next 30 years.
These demographic shifts raise important questions about the future impact of religion. Religion can be a source of both conflict and cooperation in the world. While religious differences can fuel conflict, religions also possess the potential to promote peace, social justice, humanitarian action, and environmental conservation. Religious beliefs influence various aspects of life, including gender roles and family size preferences, but these are also shaped by cultural, social, and economic factors. Understanding the evolving demographics of religion is crucial for navigating the complexities of our world and fostering greater intercultural and interreligious understanding.
