The World Bank, an international organization dedicated to helping countries overcome poverty, sorts each of the world's nations into one of four categories: high income, upper-middle income, lower-middle income, and low income. Upper-middle income countries and lower-middle income countries are known collectively as middle-income countries (MICs). In response to shifts in the global economy, the World Bank adjusts the boundary lines between the categories each July. For 2021-2022, lower middle-income nations are those with a GNI (Gross National Income) per capita of $1,046 to $4,095. Upper middle-income countries have a GNI per capita of $4,096 to $12,695.
More than half of the world's countries (110 in 2021-22, listed in the table below) are middle-income countries, which display a diverse range of regions, sizes, populations, and cultures. MICs are home to 75% of the world's population, including 62% of its poor people, and produce one-third of the global GDP. Many MICs face similar challenges, which often include population growth that outpaces the development of infrastructure, a lack of investment capital and skilled workers, and government corruption and/or instability.
Middle-income countries are essential to global economic growth. Development and growth in MICs, according to the World Bank, has positive ripple effects on other countries such as increased international trade, greater sustainable energy development, improved food and water security, and a reduction in border conflicts. If evaluated using the United Nations' overarching Human Development Index, middle-income countries tend to classify as developing countries, ranking above least-developed countries (which typically correlate to low-income countries) but falling short of developed (high-income) countries.