United States is about 1.3 times bigger than Australia.

Australia is approximately 7,741,220 sq km, while United States is approximately 9,833,517 sq km, making United States 27% larger than Australia. Meanwhile, the population of Australia is ~26.1 million people (311.2 million more people live in United States).
Tip: This to-scale comparison of Australia vs. United States uses the Mercator projection, which distorts the size of regions near the poles.
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