Religions of the world by greatest number of adherents

The numbers of adherents to organised religions in the world is difficult to accurately ascertain. Therefore figures and estimates are included from multiple sources to show the reader the problem in compiling such statistics.

• Christianity: 2.1 billion (24% - 26%)
  
• Islam: 1.3 billion (20%)
  
• Secular/Irreligious/Agnostic/Atheism: 1.1 billion (19%)
  
• Hinduism: 900 million (17%)
  
• Chinese traditional religion: 394 million
  
• Buddhism: 376 million
  
• primal-indigenous: 300 million
  
• African Traditional & Diasporic: 100 million
  
• Sikhism: 23 million
  
• Juche: 19 million
  
• Spiritism: 15 million
  
• Judaism: 14 million
  
• Baha'i: 7 million
  
• Jainism: 4.2 million
  
• Shinto: 4 million
  
• Cao Dai: 4 million
  
• Zoroastrianism: 2.6 million
  
• Tenrikyo: 2 million
  
• Neo-Paganism: 1 million
  
• Unitarian-Universalism: 800 thousand
  
• Rastafarianism: 600 thousand
  
• Pastafarianism: 550 thousand
  
• Scientology: 500 thousand