This is a list of top 100 Poorest Countries in the world as of 2018 according to the latest research by International Monetary Fund (IMF). The ranking is based on the GDP per capita of the 187 countries, which is a measure of the total output of a Country in a year divided by the number of people in that country. South Sudan is the poorest country in the world with a GDP per capita of US $228 while Luxembourg is the richest country in the world with a GDP per capita of US $105,803. The figures below are in the current US dollars.