Indonesia speaks about a tenth of the world's languages across 17,000 islands
More than half of Indonesia's roughly 284 million people live on Java, making it the most crowded island on Earth. Yet the country is also a linguistic giant, with 737 regional languages, around a tenth of all those spoken worldwide. Most Indonesians learn a local tongue at home and the national language as a bridge.
The census of 2020 counted 270.20 million people, up from 237.64 million in 2010, and an official estimate put the total at 284.44 million by mid-2025, still fourth in the world. Growth has run at a little over 1.1 percent a year despite a family planning programme dating from 1967. United Nations projections no longer expect Indonesia to overtake the United States, and see Nigeria and Pakistan passing it by 2040. A 2025 survey put the fertility rate at 2.13 children per woman, only just above replacement, and the median age was 30.2 in 2017.
About 600 ethnic groups share the archipelago. Most people descend from Austronesian peoples of the west and centre, while Melanesian peoples live in the eastern islands of Maluku, Western New Guinea and East Nusa Tenggara. The Javanese, around 40 percent of the population, have long dominated politics: every president since independence has had at least partial Javanese ancestry. The Sundanese follow at 15.4 percent, then Malays, Batak, Madurese and others.
Indonesian is the official language and is spoken by over 97 percent of people, typically as a lingua franca rather than a first language. Javanese is the leading mother tongue, with more than 80 million speakers. The west and centre are dominated by Austronesian languages such as Sundanese, Balinese and Buginese, whereas Papua and Maluku hold over 270 Papuan languages from entirely separate families, which helps make Indonesia the second most linguistically diverse country on the planet.
It is also the largest Muslim-majority nation. Registration figures from 2025 show 87.15 percent Muslim and 10.44 percent Christian, with small Hindu and Buddhist communities; most Hindus are Balinese and most Buddhists are ethnically Chinese.
Source: Demographics of Indonesia
