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Total Fertility Rate (TFR) Calculator

Calculates the average number of children a woman would have over her lifetime.

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Total Fertility Rate

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Overview

The Total Fertility Rate (TFR) is a key demographic indicator representing the average number of children a woman is expected to have during her childbearing years, assuming current age-specific fertility rates persist. It is calculated by summing the age-specific fertility rates (ASFRs) for women in 5-year age groups (typically 15-49) and multiplying by five (the width of the age interval). TFR provides a synthetic measure of fertility, independent of the age structure of the population, making it useful for comparing fertility levels across different populations or over time.

Symbols

Variables

_x = Sum of Age-Specific Fertility Rates, = Total Fertility Rate

Sum of Age-Specific Fertility Rates
children/woman
Total Fertility Rate
children/woman

Apply it well

When To Use

When to use: Use this formula to estimate the average number of children per woman in a population, providing insight into population growth potential. It's applied when you have age-specific fertility rates for different age groups within the childbearing years (15-49).

Why it matters: TFR is crucial for understanding population change, forecasting future population size, and informing policy decisions related to family planning, education, and healthcare. A TFR of approximately 2.1 is generally considered the replacement level, below which a population will eventually decline without immigration.

Avoid these traps

Common Mistakes

  • Forgetting to multiply the sum of ASFRs by 5.
  • Using ASFRs per 1000 women directly without converting to per woman.
  • Incorrectly summing ASFRs for age groups outside the 15-49 range.

One free problem

Practice Problem

A country's age-specific fertility rates (births per woman) for the 5-year age groups 15-19, 20-24, 25-29, 30-34, 35-39, 40-44, and 45-49 are 0.02, 0.15, 0.20, 0.18, 0.10, 0.03, and 0.01 respectively. Calculate the Total Fertility Rate (TFR) for this country.

Sum of Age-Specific Fertility Rates0.69 children/woman

Solve for: TFR

Hint: First, sum all the given age-specific fertility rates.

The full worked solution stays in the interactive walkthrough.

References

Sources

  1. Wikipedia: Total Fertility Rate
  2. Britannica: Total fertility rate
  3. Wikipedia: Age-specific fertility rate
  4. Weeks, John R. Population: An Introduction to Concepts and Issues. 13th ed. Cengage Learning, 2017.
  5. Preston, Samuel H., Patrick Heuveline, and Michel Guillot. Demography: Measuring and Modeling Population Processes.
  6. United Nations Department of Economic and Social Affairs, Population Division. World Population Prospects 2022. United Nations, 2022.
  7. World Bank Data, 'Fertility rate, total (births per woman)'. The World Bank Group.
  8. Centers for Disease Control and Prevention (CDC), National Center for Health Statistics (NCHS). Births: Final Data for 2022. U.S.