The United States has a capitalist mixed economy, which is fueled by abundant natural resources, a well-developed infrastructure, and high productivity. According to the International Monetary Fund, the U.S. GDP of $14.3 trillion constitutes 23% of the gross world product at market exchange rates and almost 21% of the gross world product at purchasing power parity (PPP). The largest national GDP in the world, it was about 4% less than the combined GDP of the European Union at PPP in 2007. The country ranks seventeenth in the world in nominal GDP per capita and sixth in GDP per capita at PPP. The United States is the largest importer of goods and third largest exporter, though exports per capita are relatively low. Canada, China, Mexico, Japan, and Germany are its top trading partners. The leading export commodity is electrical machinery, while vehicles constitute the leading import. The United States tops the overall ranking in the Global Competitiveness Report. After an expansion that lasted just over six years, the U.S. economy has been in recession since December 2007.

In 2009, the private sector is estimated to constitute 55.3% of the economy, with federal government activity accounting for 24.1% and state and local government activity (including federal transfers) the remaining 20.6%. The economy is postindustrial, with the service sector contributing 67.8% of GDP. The leading business field by gross business receipts is wholesale and retail trade; by net income it is finance and insurance. The United States remains an industrial power, with chemical products the leading manufacturing field. The United States is the third largest producer of oil in the world, as well as its largest importer. It is the world's number one producer of electrical and nuclear energy, as well as liquid natural gas, sulfur, phosphates, and salt. While agriculture accounts for just under 1% of GDP, the United States is the world's top producer of corn and soybeans. The New York Stock Exchange is the world's largest by dollar volume. Coca-Cola and McDonald's are the two most recognized brands in the world.

In 2005, 155 million persons were employed with earnings, of whom 80% had full-time jobs. The majority, 79%, were employed in the service sector. With about 15.5 million people, health care and social assistance is the leading field of employment. About 12% of workers are unionized, compared to 30% in Western Europe. The World Bank ranks the United States first in the ease of hiring and firing workers. Between 1973 and 2003, a year's work for the average American grew by 199 hours. Partly as a result, the United States maintains the highest labor productivity in the world. However, it no longer leads in productivity per hour as it did from the 1950s through the early 1990s; workers in Norway, France, Belgium, and Luxembourg are now more productive per hour. Compared to Europe, U.S. property and corporate income tax rates are generally higher, while labor and, particularly, consumption tax rates are lower.