There are 4,300 religions of the world, according to the findings of Adherents, a non-religious, independent organization that monitors the number and size of the world’s religions. Eighty percent of the planet’s seven billion inhabitants, however, celebrate just four of them.

Christianity

It may come as no shock to you that Christianity is the world’s largest religion. The data, which comes from the Pew Research Center, shows that nearly one-third of the population — or 2.3 billion people — subscribe to the ideals and beliefs posed by the Christian faith. However, the findings also reveal that the number of Christian followers is on the decline, especially in the United States.

According to the data, 77% of American adults identified as Christians in 2018. In 2019, however, that number fell dramatically by 12 percentage points, to 65%. From 2007 to 2019, the percentage of Protestants dropped from 51% to 43%, while the number of Catholics fell from 24% to 20%. In sub-Saharan Africa and Latin America, however, the number of followers is rising.

Islam

In terms of followers, Islam comes in at a close second, with 1.8 billion believers and growing. The religion was founded in Saudi Arabia and is based on the teachings of Prophet Muhammad. Followers, also known as “Muslims,” believe in a single God, whom they refer to as “Allah.”

Muslims fall into one of two sects: Sunni and Shia. Approximately 80% to 90% of followers transcribe to the beliefs of the Sunni, while the remaining 10% to 20% consider themselves Shia. The religion ultimately divided because of a dispute concerning succession after Muhammad’s death in 632 AD.

Unlike Christianity, the number of Islam followers is on the rise. Between 2010 and 2015, the religion saw an upsurge, which researchers attribute to the fact that there were more births than deaths during that period — approximately 152 million, to be exact.

Unaffiliated

More people are beginning to denounce religion entirely, preferring to remain neutral or devise their own beliefs. The “unaffiliated” make up the third-largest “religious” group, accounting for about one-seventh of the world’s population. The people who fall within this group subscribe to varied beliefs, as the moniker is given to anyone who identifies as agnostic, secular, atheist or non-religious. Approximately 50% are theists — meaning they believe in some higher being — but are not “religious.” The category also contains humanists.

Hinduism

Hinduism is the world’s fourth-largest religion and is made up of about 900 million followers. This religion differs greatly from the other big four in that it does not have a single founder. Moreover, it subscribes to several different scriptures and teachings, and lessons vary from place to place. The majority of Hindus live in the Indian subcontinent.

Several other religions have a substantial number of followers as well. For instance, Buddhism is the world’s fifth-largest religion and boasts 400 million followers. Taoism does not fall far behind.

The World’s Smallest Religions

On the other end of the spectrum are the religions that are so small they are in danger of disappearing altogether. Two of those religions are as follows:

• Druze: Druze is around 1,000 years old and focuses its theology on truthfulness, reincarnation and purity of the mind. This belief is a hybrid of Greek philosophy, Islam and Judaism. To date, there are only one million believers remaining.
• Zoroastrianism: Zoroastrianism is one of the oldest beliefs in the world and is based on the teachings of the Iranian prophet Zoroaster. Zoroastrians believe in a higher deity, whom they call Ahura Mazda, and a devil entity, whom they refer to as Angra Mainyu. They believe in hell, but unlike followers of Christian denominations, they do not believe in eternal damnation. Rather, Angra Mainyu doles out a punishment that fits the crime. Researchers estimate that approximately 200,000 Zoroastrians remain.

Religions come in all sizes. However, each has its own unique impact on the world.