The common association of Islam with the Arab world understates its reach considerably. Arabs are a minority of Muslims. The largest Muslim populations are in South and Southeast Asia, chiefly Indonesia, Pakistan, India and Bangladesh, and the Asia-Pacific region holds more Muslims than the Middle East and North Africa and sub-Saharan Africa together.
By the Pew Research Center's counts the global Muslim population rose from about 1.7 billion in 2010 to about 2.0 billion in 2020, growing roughly twice as fast as the world's population and moving from 24 to 26 per cent of it. That growth is mainly demographic, a matter of a younger population and higher fertility, rather than of conversion, and it is fastest in sub-Saharan Africa.
Arabic remains the language of prayer everywhere, which gives the religion a textual unity its geography might not suggest. Practice nonetheless varies widely with local custom, legal school and the degree to which the state involves itself in religion. Muslim-majority countries range from the constitutionally secular to those where classical law is enforced by the state, and the proper relationship between religious and political authority is argued over in all of them.
Substantial Muslim minorities live in Western Europe, North America, Russia, China and elsewhere, some through twentieth-century migration and some long-settled and indigenous, and their legal and social circumstances differ sharply from one country to the next.