“Most practiced religions” sounds simple, but global religious demography depends on definitions. Pew Research Center’s latest comprehensive global comparison estimates religious identity in 2020 across seven broad categories. One of those categories—the religiously unaffiliated—is not a religion at all.
Spiritual Culture therefore uses the heading “largest religious groups” while clearly separating religious traditions from demographic categories.
Global religious composition in 2020
| Category | Approximate 2020 population | Share of world population |
|---|---|---|
| Christianity | 2.3 billion | 28.8% |
| Islam | 2.0 billion | 25.6% |
| Religiously unaffiliated | 1.9 billion | 24.2% |
| Hinduism | 1.2 billion | 14.9% |
| Buddhism | 324 million | 4.1% |
| Other religions combined | combined demographic category | 2.2% |
| Judaism | 14.8 million | about 0.2% |
Christianity
Christianity remained the largest broad religious group in Pew’s 2020 estimates. Its worldwide population increased from 2010 to 2020, but its share of humanity declined because global population growth was faster and many people in some countries disaffiliated from Christianity.
Islam
Islam was the fastest-growing major religious group between 2010 and 2020. Pew estimates that Muslims increased by about 347 million during the decade, reaching roughly 2.0 billion people.
The religiously unaffiliated are not a religion
About 1.9 billion people identified with no religion in 2020, including atheists, agnostics, and people who simply answered that they had no religious affiliation. This category belongs in a demographic table but should not be described as the world’s “third-largest religion.”
Hinduism
Hindus numbered nearly 1.2 billion and remained about 15% of the global population. Hinduism is unusually concentrated geographically: about 95% of the world’s Hindus lived in India.
Buddhism
Pew’s revised estimates put the global Buddhist population at about 324 million in 2020. Buddhism was the only major religious group in the study to decline in absolute numbers from 2010 to 2020.
Judaism
Pew estimated about 14.8 million Jews worldwide in 2020. Judaism is numerically much smaller than Christianity, Islam, Hinduism, or Buddhism, but population size says little about a tradition’s historical, theological, or cultural influence.
What “other religions” means
Pew combines many traditions into an “other religions” category because global data is not sufficiently comparable to estimate each of them separately in the same model. This category includes Bahá’ís, Daoists, Jains, Shinto practitioners, Sikhs, Zoroastrians, adherents of folk or traditional religions, and many smaller communities.
Grouping them for demography does not mean they form one religion.
Why older global rankings differ
Pew revised its 2010 estimates after incorporating new censuses and better information, especially for China and East Asia. This substantially changed earlier estimates for Buddhists, the unaffiliated, and folk/traditional religion categories.
