Major Religions of the World
Ranked by Number of Adherents

(Sizes shown are approximate estimates, and are here mainly for the purpose of ordering the groups, not providing a definitive number. This list is sociological/statistical in perspective.)

1. Christianity: 2.1 billion
   
2. Islam: 1.5 billion
   
3. Secular/Nonreligious/Agnostic/Atheist: 1.1 billion
   
4. Hinduism: 900 million
   
5. Chinese traditional religion: 394 million
   
6. Buddhism: 376 million
   
7. primal-indigenous: 300 million
   
8. African Traditional & Diasporic: 100 million
   
9. Sikhism: 23 million
   
10. Juche: 19 million
    
11. Spiritism: 15 million
    
12. Judaism: 14 million
    
13. Baha'i: 7 million
    
14. Jainism: 4.2 million
    
15. Shinto: 4 million
    
16. Cao Dai: 4 million
    
17. Zoroastrianism: 2.6 million
    
18. Tenrikyo: 2 million
    
19. Neo-Paganism: 1 million
    
20. Unitarian-Universalism: 800 thousand
    
21. Rastafarianism: 600 thousand
    
22. Scientology: 500 thousand
    

Introduction
The adherent counts presented in the list above are current estimates of the number of people who have at least a minimal level of self-identification as adherents of the religion. Levels of participation vary within all groups. These numbers tend toward the high end of reasonable worldwide estimates. Valid arguments can be made for different figures, but if the same criteria are used for all groups, the relative order should be the same. Further details and sources are available below and in the Adherents.com main database.