Net migration is the difference between the number of immigrants (people coming into an area) and the number of emigrants (people leaving an area) divided by the population. It is the net total of migrants during a period, that is, the number of immigrants minus the number of emigrants, including both citizens and non-citizens. Net migration can be positive, negative, or balanced. A positive net migration rate occurs when the number of immigrants is larger than the number of emigrants, indicating that more people are entering than leaving an area. Conversely, a negative net migration rate occurs when more people emigrate from a country, meaning that more people are leaving than entering the area. When there is an equal number of immigrants and emigrants, the net migration rate is balanced.

Net migration is a crucial factor in every country, as it plays a significant role in determining the countrys economic and social development. A high net migration rate is often seen as a sign of a wealthy and developed country, while a low net migration rate is seen as a sign of an undeveloped country with political problems and lacking resources its citizens need. Net migration can be due to various factors, including economic, social, and environmental factors.

It is essential to note that the net migration rate does not distinguish between economic migrants, refugees, and other types of migrants, nor does it distinguish between lawful migrants and undocumented migrants. The quality and quantity of data used in the estimation and projection of net migration vary considerably by country, and the movement of people across international boundaries is subject to a great deal of volatility.