# Fertility rate: definition and caveats

## What it measures

Total fertility rate: the average number of children a woman would have if she experienced the year's age-specific birth rates throughout her childbearing years. Unit: live births per woman.

## Key points from Our World in Data

- The UN's projections come in several scenarios. The medium scenario is the central estimate; the high and low scenarios are designed to fully reach 0.5 births per woman above and below the medium from the mid-2030s onward (e.g. medium 2.1 → high 2.6, low 1.6). In the first decade of the projection the gap is narrower (about ±0.25 in 2024–2028, ±0.4 in 2029–2033). The constant-fertility scenario keeps fertility at its current level, and the zero-migration scenario uses the same fertility as the medium scenario.

## How Our World in Data processed it

The UN doesn't publish a total fertility rate for our continental aggregates (Africa, Asia, Europe, North America, South America, Oceania), since its own regional groupings differ. We derive these by summing the age-specific fertility rates across the 5-year reproductive age groups (15–19 to 45–49) and multiplying by 5, where each age-specific rate uses regional totals for births and female population.

[Source and producers](/sources/fertility) · [All fertility rate figures](/fertility).

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