The U.S. government estimates the total population at 80.5 million (July 2018 estimate).  Unofficial estimates based on the census and figures provided by religious groups indicate approximately 29 percent of the population is Roman Catholic, and 27 percent belongs to the EKD – a confederation of Lutheran, Reformed (Calvinist), and United (Prussian Union) Protestant regional churches.  Other Protestant denominations, including the New Apostolic Church, Baptist communities, and nondenominational Christians, combined account for less than 1 percent of the population.  Orthodox Christians represent 2.4 percent of the population.

According to government estimates, approximately 6.3 percent of the population is Muslim, of which 75 percent is Sunni, 13 percent Alevi, and 7 percent Shia; the remainder identifies simply as “Muslim.”  According to the Ministry of Interior, approximately 25 percent of Muslims are recent immigrants; between 2011 and 2015, an estimated 1.2 million refugees arrived from predominately Muslim countries.  Estimates of the Jewish population vary widely; the Central Council of Jews estimates it at 200,000.  The Central Welfare Office for Jews in Germany reported that Jewish communities had approximately 100,000 members at the end of 2017.  According to Religious Studies Media and Information Service (REMID), a secular, religious studies NGO, groups that together constitute less than 1 percent of the population include Buddhists (270,000); Jehovah’s Witnesses (222,000); Hindus (100,000); Yezidis (100,000); The Church of Jesus Christ of Latter-day Saints (Church of Jesus Christ) (40,000); Sikhs (15,000); and COS (5,000-10,000).  All of REMID’s estimates are based only on members who have registered with a religious group.  According to the nonprofit Research Group Worldviews Germany, approximately 36 percent of the population either has no religious affiliation or belongs to religious groups not counted in the government’s statistics.

The U.S. government estimates the total population at 262.8 million (July 2018 estimate).  According to the 2010 census, approximately 87 percent of the population is Muslim, 7 percent Protestant, 3 percent Roman Catholic, and 1.5 percent Hindu.  Those identifying with other religious groups, including Buddhism, traditional indigenous religions, Confucianism, and other Christian denominations, and those who did not respond to the census question comprise approximately 1.3 percent of the population.

The Muslim population is overwhelmingly Sunni.  An estimated one to three million Muslims are Shia.  Many smaller Muslim groups exist; estimates put the total number of Ahmadi Muslims at 200,000 to 400,000.

Many religious groups incorporate elements of Islam, Hinduism, and Buddhism, making it difficult to disaggregate the exact number of followers.  An estimated 20 million people, primarily in Java, Kalimantan, and Papua, practice various traditional belief systems, often referred to collectively as aliran kepercayaan.  There are approximately 400 different aliran kepercayaan communities throughout the archipelago.

There is a Sikh population estimated at between 10,000 and 15,000, with approximately 5,000 in Medan and the rest in Jakarta.  There are very small Jewish communities in Jakarta, Manado, Jayapura, and elsewhere.  The Baha’i Faith and Falun Dafa (or Falun Gong) communities report thousands of members, but independent estimates are not available.  The number of atheists is also unknown, but the group Indonesian Atheists states it has more than 700 members.

The province of Bali is predominantly Hindu, and the provinces of Papua, West Papua, East Nusa Tenggara, and North Sulawesi are predominantly Christian.