South Africa is in the late phase of Stage 3 of the demographic transition model, approaching Stage 4. Its birth rate has fallen significantly over the past two decades, its death rate has declined after a sharp spike driven by HIV/AIDS, and its fertility rate of 2.21 children per woman in 2025 is nearly at the replacement level of 2.1. These indicators place the country at the tail end of Stage 3, where both birth and death rates are low and population growth is slowing but still positive.
Why Late Stage 3, Not Stage 4
In the classic demographic transition model, Stage 3 is defined by falling birth rates catching up to already-low death rates, producing slower population growth. Stage 4 arrives when birth and death rates are both low and roughly in balance, leading to very slow or near-zero population growth. South Africa sits right at the boundary. Its fertility rate dropped from 2.78 children per woman in 2008 to 2.21 in 2025, just a hair above the 2.1 replacement threshold. Population growth in 2024 was 1.33%, which is moderate but not yet the near-zero rate typical of Stage 4 countries.
Academic researchers have described South Africa’s demographic transition as “substantially complete” and “almost finished.” The country was already well advanced in its transition before the HIV/AIDS crisis of the 1990s and 2000s disrupted the trajectory. Without that disruption, South Africa would likely have entered Stage 4 years ago.
How HIV/AIDS Distorted the Pattern
South Africa’s path through the demographic transition model is unusual because the HIV/AIDS epidemic temporarily reversed its death rate decline. HIV prevalence among pregnant women visiting public clinics rose from 0.8% in 1990 to 29.5% by 2011. Between 2001 and 2006, the average mortality risk of South Africans increased by roughly 50%, with the heaviest toll falling on adults aged 18 to 59. This spike in deaths meant the country’s death rate climbed even as its birth rate was falling, a pattern that doesn’t fit neatly into any single DTM stage.
The rollout of free antiretroviral therapy changed the picture dramatically. By 2011, mortality had fallen back to its 2001 level, and the decline has continued since. Life expectancy at birth in 2025 is estimated at 64.0 years for males and 69.6 years for females. These figures are still lower than in many Stage 4 countries (where life expectancy often exceeds 75), but they represent a significant recovery and ongoing improvement.
Birth Rate and Fertility Trends
The clearest signal that South Africa is finishing Stage 3 comes from its fertility data. A total fertility rate of 2.21 is close to replacement level and far below the rates seen in Stage 2 or early Stage 3 countries, where women typically have 4 to 6 children. The decline has been steady and driven by the same factors seen in other transitioning countries: urbanization, greater access to education (especially for women), and wider availability of contraception.
The child dependency ratio, which measures how many children under 15 depend on every 100 working-age adults, dropped from 41.7 in 2002 to 33.1 in 2024. Fewer children relative to working-age adults is a hallmark of late Stage 3 and signals that the country is entering a potential “demographic dividend” period, where a large share of the population is of working age.
What the Age Structure Looks Like
South Africa’s population pyramid is shifting from the broad base typical of younger, faster-growing countries toward the more rectangular shape seen in Stage 4 nations. The old-age dependency ratio (people 65 and older per 100 working-age adults) rose from 8.3 in 2002 to 9.9 in 2024. That increase is modest compared to fully developed countries, but the direction is clear: the population is aging as birth rates fall and life expectancy rises.
The country’s total population surpassed 63 million in 2024, growing by about 835,500 people that year. That growth comes from a combination of natural increase (more births than deaths) and immigration. In a fully Stage 4 country, natural increase is minimal, and population changes are often driven more by migration than by the gap between births and deaths. South Africa isn’t there yet, but it’s heading in that direction.
How South Africa Compares Within Africa
South Africa is one of the most demographically advanced countries on the African continent. Most sub-Saharan African nations are in Stage 2 or early Stage 3, with high birth rates and rapidly declining death rates producing fast population growth. South Africa’s fertility rate of 2.21 is closer to that of countries like Brazil or Turkey than to its regional neighbors, many of which have fertility rates above 4.0. This makes South Africa something of an outlier in the region and a case study that researchers frequently point to as evidence that the demographic transition is not limited to high-income countries.
The Complicating Factors
Placing South Africa precisely on the demographic transition model is harder than it looks because the model assumes a smooth, linear progression. South Africa’s experience has been anything but smooth. The HIV/AIDS epidemic pushed the death rate in the wrong direction for over a decade. Infant mortality, at about 34 per 1,000 live births (under-five rate as of 2022), remains higher than in most Stage 4 countries, where that figure is typically in the single digits. And persistent inequality means that different segments of the population are effectively at different stages of the transition: wealthier, urban South Africans have demographic profiles resembling Stage 4 countries, while poorer, rural communities may still reflect Stage 3 or even late Stage 2 patterns.
The most accurate summary is that South Africa is in late Stage 3 with strong momentum toward Stage 4. Its fertility rate is nearly at replacement level, its death rate has recovered from the HIV crisis, and its population is aging. Within the next decade or two, if current trends hold, the country will likely cross into Stage 4 by most standard definitions.