Net migration is the difference between the number of immigrants (people who move into a country) and the number of emigrants (people who move out of a country) during a specific period of time, usually a year. It is a measure of how much the population of a country is changing due to international migration. If more people are coming into the country than leaving, the net migration is positive, and if more people are leaving than coming in, the net migration is negative. Net migration is an important indicator of population growth and demographic changes in a country.