United States is 18% larger than Australia.
The United States of America, commonly referred to as the United States, America, and sometimes the States, is a federal republic consisting of 50 states and a federal district. The 48 contiguous states and Washington, D.C., are in central North America between Canada and Mexico. Wikipedia
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