What GDP is

GDP, gross domestic product, is the total value of all the goods and services an economy produces over a set period, usually a quarter or a year. It is the broadest single measure of how big an economy is and how fast it is growing. When you read that an economy grew 2 percent, or shrank, that is GDP changing.

Three ways to measure the same thing

GDP can be counted three ways that, in theory, give the same total. You can add up everything produced, add up all the spending on it, or add up all the income earned from making it. The spending version is the most quoted: consumer spending, business investment, government spending, and exports minus imports. In most large economies, consumer spending is by far the biggest piece, which is why the health of the shopper matters so much to the headline figure.

Real versus nominal

There is one trap to avoid. Nominal GDP is measured in current prices, so it rises when prices rise even if nothing more is actually produced. Real GDP strips out inflation to show the true change in output. When economists talk about growth, they almost always mean real GDP, because that is the number that reflects more stuff, not just higher prices.

GDP and recessions

A common rule of thumb is that two quarters in a row of falling real GDP signal a recession. It is a useful shorthand, but not the official definition in the United States, where a separate committee weighs several measures, including jobs and incomes, before dating a recession. Still, GDP is the number markets watch first for signs the economy is turning.

What GDP leaves out

GDP is powerful precisely because it is simple, and that is also its weakness. It measures the size of the pie, not how the slices are shared, so it can rise while wages stagnate or inequality widens. It ignores unpaid work, such as caring for a family, and it does not subtract environmental damage. A country can grow its GDP in ways that leave many people no better off, which is why economists read it alongside wages, inflation and the jobs report.

Why markets and the Fed watch it

Because GDP captures the whole economy, it shapes big decisions. Central banks such as the Federal Reserve weigh growth against inflation when setting interest rates, as our explainer on how the Federal Reserve works describes. Investors read GDP for signs of where profits and interest rates are heading. A surprise, in either direction, can move stock and bond markets.

GDP per person

A bigger economy is not the same as a richer population. A country with a huge GDP can still have low living standards if that output is spread across a very large population. For that reason economists often use GDP per capita, the total divided by the number of people, to compare living standards between countries or over time. It is a rough measure, since it says nothing about distribution, but it is a better guide to typical prosperity than the headline total.

How often it is measured

In the United States, GDP is estimated every quarter and revised more than once as fuller data arrives, so an early reading can change. That is worth remembering when a single quarter's figure drives headlines: the first estimate is a draft, not the final word.

The bottom line

GDP is the single broadest gauge of an economy's size and growth, best read as real GDP, which strips out inflation. It tells you how big the economy is, not how well its gains are shared or what they cost, so it is a starting point rather than the whole story. Read it beside jobs, wages and inflation, and it becomes genuinely useful. The glossary defines the terms.