Gross Domestic Product (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 or a quarter. GDP is an important indicator of a country's economic health and is used to compare the economic performance of different nations. There are three main approaches to calculating GDP: the production approach, the income approach, and the expenditure approach. Each method provides a different perspective on the economy, but they all aim to capture the same overall economic activity. Understanding GDP helps policymakers and economists make informed decisions about economic growth and development.