The simplest way to explain it is that the GDP includes all of the goods that have been produced in a specific time frame, usually one year. The GDP is measured for each country separately, though it can also be measured by organization, region, etc. To be more specific, the final goods that the GDP includes in it include all of the public and private consumption, investments, construction costs, government outlays, additions to private inventories, as well as the foreign trade balance. The GDP is often used to describe a country's economy and the living standard, but it is far from the best measure for those things.
