The United States has a highly developed diversified market economy. It is the world's largest economy by nominal GDP and second largest by purchasing power parity (PPP). As of 2025, it has the world's seventh highest nominal GDP per capita and ninth highest GDP per capita by PPP. According to the World Bank, the U.S. accounted for 14.8% of the global aggregate GDP in 2024 in purchasing power parity terms and 26.2% in nominal terms. The U.S. dollar is the currency most used in international transactions and the world's foremost reserve currency, backed by a large U.S. treasuries market, its role as the reference standard for the petrodollar system, and its linked eurodollar. Several countries use it as their official currency and in others it is the de facto currency. Since the end of World War II, the economy has achieved relatively steady growth, low unemployment and inflation, and rapid advances in technology.

The American economy is fueled by high productivity, well-developed transportation infrastructure, and extensive natural resources. Americans have the sixth highest average household and employee income among OECD member states. In 2021, they had the highest median household income among OECD countries, although the country also had one of the world's highest income inequalities among the developed countries. The largest U.S. trading partners are Mexico, Canada, China, Japan, Germany, South Korea, the United Kingdom, Taiwan, India, and Vietnam. The U.S. is the world's largest importer and second-largest exporter. It has free trade agreements with several countries, including Canada and Mexico (through the USMCA), Australia, South Korea, Israel, and several others that are in effect or under negotiation. The U.S. has a highly flexible labor market, where the industry adheres to a hire-and-fire policy, and job security is relatively low. Among OECD nations, the U.S. has a highly efficient social security system; social expenditure stood at roughly 30% of GDP.

The United States is the world's largest producer of petroleum, natural gas, and blood products. In 2024, it was the world's largest trading country, and second largest manufacturer, with American manufacturing making up a fifth of the global total. The U.S. has the largest internal market for goods, and also dominates the services trade. Total U.S. trade was $7.4 trillion in 2023. Of the world's 500 largest companies, 139 are headquartered in the U.S. The U.S. has the world's highest number of billionaires, with total wealth of $5.7 trillion. U.S. commercial banks had $22.9 trillion in assets in December 2022. U.S. global assets under management had more than $30 trillion in assets. During the Great Recession of 2008, the U.S. economy suffered a significant decline. The American Reinvestment and Recovery Act was enacted by the United States Congress, and in the ensuing years the U.S. experienced the longest economic expansion on record by July 2019.

The New York Stock Exchange and Nasdaq are the world's largest stock exchanges by market capitalization and volume of transactions. The U.S. has the world's largest gold reserves, with over 8,000 tonnes of gold. In 2014, the U.S. economy was ranked first in international ranking on venture capital and global research and development funding. As of 2024, the U.S. spends around 3.46% of GDP on cutting-edge research and development across various sectors of the economy. Consumer spending comprised 68% of the U.S. economy in 2022, while its labor share of income was 44% in 2021. The U.S. has the world's largest consumer market. The nation's labor market has attracted immigrants from all over the world and its net migration rate is among the highest in the world. The U.S. is one of the top-performing economies in studies such as the Ease of Doing Business Index, the Global Competitiveness Report, and others.

The economic history of the United States began with British settlements along the Eastern seaboard in the 17th and 18th centuries. After 1700, the United States gained population rapidly, and imports as well as exports grew along with it. Africa, Asia, and most frequently Europe, contributed to the trade of the colonies. These 13 colonies gained independence from the British Empire in the late 18th century and quickly grew from colonial economies towards an economy focused on agriculture.

In 180 years, the United States grew to become a huge, integrated, and industrialized economy, which made up about a fifth of the world economy. In that process, the U.S. GDP per capita rose past that of many other countries, supplanting the British Empire at the top. The economy maintained high wages, attracting immigrants by the millions from all over the world. In the 1820s and 1830s, mass production shifted much of the economy from artisans to factories. New government regulations strengthened patents.

Early in the 19th century, more than 80 percent of Americans engaged in farming. Most of the manufacturing centered on the first stages of the transformation of raw materials, with lumber and sawmills, textiles, and boots and shoes leading the way. The rich natural resources contributed to the rapid economic expansion of the nineteenth century. Ample land allowed the number of farmers to keep growing; but activity in manufacturing, services, transportation, and other sectors grew much faster, so that by 1860 the population was only about 50 percent rural, down from over 80 percent.

In the 19th century, recessions frequently coincided with financial crises. The Panic of 1837 was followed by a five-year depression, marked by bank failures and unprecedented unemployment. Because of the great changes in the economy over the centuries, it is difficult to compare the severity of modern recessions to that of early recessions. Recessions after World War II appear to have been less severe than earlier recessions, but the reasons for this are unclear.