GDP, or Gross Domestic Product, is the total monetary value of all finished goods and services produced within a country's borders during a specific time period, usually a year or quarter. It serves as the most comprehensive measure of a nation's overall economic activity and health.
Steps
Identify all final goods and services produced domestically within the time period, making sure to count only finished products to avoid double-counting intermediate goods.
Use one of three main approaches: the expenditure approach (adding up all spending), the income approach (adding up all earnings), or the production approach (adding up value added at each production stage).
For the expenditure approach, sum consumption spending by households, investment by businesses, government spending on goods and services, and net exports (exports minus imports).
Express the result in the country's currency and adjust for inflation if calculating real GDP rather than nominal GDP.
Compare the GDP figure to previous periods or other countries to assess economic growth, contraction, or relative economic size.
Worked example
Using the expenditure method for a simplified economy: If households spend $500 billion on goods and services, businesses invest $150 billion in equipment and buildings, the government spends $200 billion, and the country exports $100 billion while importing $80 billion, then GDP = 500 + 150 + 200 + (100 - 80) = $970 billion.
Remember
GDP measures the total value of everything a country produces in a given period and can be calculated by adding up all spending, all income, or all value added in the economy.