United States is approximately 9,833,517 sq km, while Singapore is approximately 719 sq km, making Singapore 0.01% the size of United States. Meanwhile, the population of United States is ~332.6 million people (326.4 million fewer people live in Singapore).
This to-scale map shows a size comparison of United States compared to Singapore. For more details, see an in-depth quality of life comparison of Singapore vs. United States using our country comparison tool.