totalfertilitetsrate

Totalfertilitetsrate, commonly referred to as the total fertility rate (TFR), is a demographic measure of the average number of children a woman would bear over her lifetime if she experienced the age-specific fertility rates of a given population throughout her reproductive years (roughly ages 15 to 49). It is usually expressed as births per woman.

Calculation typically involves summing the age-specific fertility rates (ASFR) for the 5-year age groups from 15–19 to 45–49. If ASFR are stated as births per woman per year, the sum is multiplied by the width of the age interval (usually 5 years). If ASFR are per 1,000 women, the calculation is TFR = Σ ASFR_i × 5 / 1000.

Interpretation and use: The TFR provides a snapshot of the level of fertility in a population and is often used to gauge population growth and replacement prospects. A TFR around 2.1 births per woman is commonly regarded as the replacement level in populations with moderate mortality and balanced sex ratios. The metric facilitates cross-country and temporal comparisons and informs population projections and policy discussions.

Limitations: TFR is a period measure based on current rates and does not predict future fertility if conditions change. It can be affected by tempo effects (delays in childbearing) and by migration or changes in mortality, which may distort comparisons. Related measures include the age-specific fertility rate (ASFR), crude birth rate (CBR), and reproduction measures such as the gross and net reproduction rates.