Adherents of Islam constitute the world 's second largest religious group. According to a study in 2015, Islam has 1.8 billion adherents, making up about 24 % of the world population. Most Muslims are either of two denominations: Sunni (80 - 90 %, roughly 1.5 billion people) or Shia (10 -- 20 %, roughly 170 - 340 million people). Islam is the dominant religion in the Central Asia, Indonesia, Middle East, South Asia, North Africa, the Sahel and some other parts of Asia. The diverse Asia - Pacific region contains the highest number of Muslims in the world, easily surpassing the Middle East and North Africa.
what is the islamic population in the world
1.8 billion