About: The total fertility rate (TFR) is the average number of children a woman would give birth to during her lifetime if she were to pass through her childbearing years (15-49 years) experiencing the present day age-specific fertility rates.
Detail: It is calculated by totalling the age-specific fertility rates as defined over five-year intervals. Assuming no net migration and unchanged mortality, a total fertility rate of 2.1 children per woman ensures a broadly stable population. Together with mortality and migration, fertility is an element of population growth, reflecting both the causes and effects of economic and social developments.
According to the United Nations Population Division, a TFR of about 2.1 children per woman is called replacement-level fertility. If replacement level fertility is sustained over a sufficiently long period, each generation will exactly replace itself.