Gross Domestic Product, or GDP, is a measure of the total economic output of a country. It represents the value of all goods and services produced within a nation's borders over a specific time period, usually a year. GDP helps economists and policymakers understand the size and health of an economy, making it easier to compare economic performance between different countries. There are three main ways to calculate GDP: the production approach, which adds up all the value added at each stage of production; the income approach, which sums up all incomes earned by individuals and businesses; and the expenditure approach, which totals all spending on goods and services. Each method provides valuable insights into how an economy functions.