Australia is 4.1 times larger than Indonesia.
Area: 7,741,220 km2 World Factbook
Population: 22,507,617 (July 2014) World Factbook
Australia, officially the Commonwealth of Australia, is a country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. It is the world's sixth-largest country by total area. Wikipedia
Area: 1,904,569 km2 World Factbook
Population: 253,609,643 (July 2014) World Factbook
Indonesia, officially the Republic of Indonesia, is a sovereign state in Southeast Asia and Oceania. Indonesia is an archipelago comprising 13,466 islands. Wikipedia