Total fertility rate (TFR) is basically the total number of kids women within a region can potentially have during their lifetimes or childbearing years, which is generally 15-44 years. In other words, the rate simply attempts to predict the total number of kids a woman could give birth to till she is 44 years of age. This assumption is done based on the number of kids women who’ve currently passed the age barrier have.
TFR is calculated to predict population decline or growth. The figures are based on assumptions and not real women fertility checks, since that would involve the impractical task of waiting through every woman’s childbearing phase. In other words, TFR is a hypothetical measure.
Generally, TFR is higher in developing Asian and African countries than the West and developed Asian economies. The lower TFR in First World nations could be attributed to either the couples’ unwillingness to have more kids or their inability to give births, thanks to their predominantly unhealthy lifestyles.