Roughly 29.4 percent of the world’s population, close to 2.3 billion people, is under the age of 18, according to U.S. Census Bureau international estimates for 2024. That share varies so dramatically by country that it produces one of the widest ranges of any demographic indicator: in Niger, 56.7 percent of the population is under 18, while in Monaco, the figure is just 11.7 percent, a gap of 45 percentage points between two countries measured in the same year.
How Many Children Live in the World Today?
Global child population statistics use two overlapping but distinct definitions: under 18, the threshold used in most social and legal contexts, and under 15, the threshold more commonly used in core demographic and fertility-related indicators.
This distinction matters because a country’s under-18 and under-15 shares can differ by six to eight percentage points, and mixing the two without clarifying which is being used produces figures that appear inconsistent even when both are accurate. Using the under-18 definition, the U.S. Census Bureau’s Vintage 2024 estimates place the global child share at 29.4 percent of the total population, compared with 21.5 percent in the United States.
Using the under-15 definition, the world’s population of children rose from approximately 1.4 billion to 1.8 billion between the early 1990s and early 2020s, according to UN Statistics Division analysis, though that number is projected to begin a slow decline around the mid-2020s as global fertility continues falling.
World Child Population by Definition
| Definition | Approximate Global Total | Approximate Share of World Population | Approximate Year |
|---|---|---|---|
| Under 15 | 1.8 billion | approximately 22 to 23% | Early 2020s |
| Under 18 | approximately 2.3 to 2.4 billion | 29.4% | 2024 |
Source: United Nations Statistics Division, The World’s Women 2020 report series; U.S. Census Bureau, Vintage 2024 Population Estimates and International Database.
Where Do Most of the World’s Children Live?
Geographic concentration of the world’s child population is heavily skewed toward the developing world. According to UN Statistics Division data, 88 percent of the world’s children live in developing regions, with Asia alone accounting for 60 percent of the global total, though Asia’s absolute number of children has been on a gently declining path as regional fertility falls, moving from roughly 1.083 billion to a projected 1.036 billion between 2000 and 2020.
Africa presents the opposite trajectory: its child population has been rising by roughly 100 million over the same comparison period, a direct consequence of the continent’s later and slower fertility decline relative to Asia and Latin America.
Countries With the Largest Child Populations
Ranking by sheer number of children favors large, populous countries regardless of their percentage share, since even a moderate child share applied to an enormous total population produces a very large absolute count.
India, Nigeria, China, Pakistan, and Indonesia, all among the world’s most populous nations, rank among the countries with the largest absolute child populations, though their percentage shares vary considerably: China’s aggregate population skews much older than Nigeria’s or Pakistan’s, giving it a comparatively smaller child share despite its enormous total population.
Countries Where Children Make Up the Largest Share
Percentage share tells an entirely different story from absolute count, and it is dominated overwhelmingly by countries in sub-Saharan Africa and parts of South Asia with the highest fertility rates in the world.
Countries With the Highest Share of Population Under Age 18, 2024
| Rank | Country | Share Under Age 18 |
|---|---|---|
| 1 | Niger | 56.7% |
| 2 | Somalia | 54.8% |
| 3 | Uganda | 54.1% |
| 4 | Mali | 53.5% |
| 5 | Angola | 53.4% |
| 6 | Chad | 52.9% |
| 7 | Congo (Kinshasa/DRC) | 52.4% |
| 8 | Benin | 51.8% |
| 9 | Mozambique | 51.5% |
| 10 | Afghanistan | 49.4% |
Source: U.S. Census Bureau, Vintage 2024 Population Estimates and November 2024 International Database Release.
Countries With the Lowest Share of Population Under Age 18, 2024
| Rank | Country | Share Under Age 18 |
|---|---|---|
| 1 | Monaco | 11.7% |
| 2 | South Korea | 13.3% |
| 3 | Bosnia and Herzegovina | 14.3% |
| 4 | Taiwan | 14.6% |
| 5 | Italy | 14.8% |
| 6 | Japan | 14.9% |
| 7 | Andorra | 15.1% |
| 8 | Ukraine | 15.3% |
| 9 | Hong Kong | 15.4% |
| 10 | Qatar | 15.4% |
Source: U.S. Census Bureau, Vintage 2024 Population Estimates and November 2024 International Database Release.
How the Global Child Population Has Changed
Regional child-share trends over the past two decades tell a consistent story of decline nearly everywhere, at very different speeds. UNICEF’s State of the World’s Children 2024 report finds that Africa’s child population share is projected to fall below 40 percent by 2050, down from about 50 percent in the 2000s, a meaningful decline but one that leaves Africa’s child share still far above the rest of the world’s.
East Asia and Western Europe, by contrast, have already seen their child shares fall by roughly 17 percentage points compared to their 2000s levels, reaching considerably lower current shares of 29 percent and 20 percent respectively for those two regions during the 2000s baseline period, illustrating how much further along those regions already were in the same transition Africa is now experiencing.
Why the Number of Children Is Changing
Three demographic mechanisms explain both the historical rise in global child numbers and the plateau now underway. Fertility decline is the dominant force reducing child numbers over time, as the global fertility rate has fallen from roughly 5 births per woman in the 1950s to 2.25 in 2024, directly reducing the number of children each successive generation of parents produces.
Falling child mortality has worked in the opposite direction historically, since UNICEF data shows child deaths under age five have fallen from 9.8 million in 2000 to 5.4 million more recently, meaning a larger share of each birth cohort now survives into the counted child population rather than dying in infancy or early childhood.
Regional population momentum, the continued growth of the number of women in reproductive ages even as fertility per woman falls, explains why Africa’s child population kept rising even through a period of declining regional fertility, a pattern distinct from Asia’s, where the reproductive-age population growth had already slowed enough for child numbers to begin falling even before fertility approached Africa’s lower levels.
What a Large Child Population Means
A very high child share creates concrete, quantifiable pressure on specific public systems well before those children reach working age. Education systems in high-child-share countries face continuous pressure simply to keep pace with enrollment growth, separate from any effort to improve teaching quality, since UNICEF reports that an additional 130 million children have entered school globally since 2000, 60 percent of them girls, even as 262 million children remain out of school worldwide.
Child protection systems face parallel strain: UNICEF data shows about one in four of the world’s 2.3 billion children under 18 have experienced disruption to childhood through early marriage, early pregnancy, exclusion from education, or malnutrition, with child marriage rates and case numbers heavily concentrated in the same high-child-share countries that top the percentage rankings above; Africa alone is projected to see its number of child brides rise from 125 million currently to as many as 310 million by 2050 if current trends continue, a rise UNICEF attributes to the combination of slow reduction rates and rapid underlying population growth rather than a growing rate of child marriage itself.
The Future of the Global Child Population
The UN Statistics Division’s own analysis projects that the global under-15 population, having grown from roughly 1.4 to 1.8 billion over recent decades, will begin a slow numerical decline starting around 2025, even as the under-18 population in absolute terms continues rising more gradually for a longer period due to population momentum in the highest-fertility regions.
This divergence between regions is expected to sharpen rather than narrow over the coming decades: UNICEF’s modeling for 2050 shows Africa’s child population share falling only to just under 40 percent even as East Asia’s and Western Europe’s shares continue falling from levels already far below that, meaning the geographic concentration of the world’s children in fewer, higher-fertility countries is likely to become even more pronounced by mid-century than it is today.
Conclusion
The global child population sits at a genuine turning point: after decades of continuous growth that took the under-15 population from 1.4 billion to 1.8 billion, the UN projects a slow decline beginning around 2025, even as the geographic concentration of the world’s remaining children continues shifting toward sub-Saharan Africa.
The 45-percentage-point gap between Niger’s 56.7 percent child share and Monaco’s 11.7 percent is not a temporary anomaly; it reflects two countries at opposite ends of the same demographic transition, and UNICEF’s own projections suggest that gap, while narrowing slightly by 2050, will remain one of the widest in global demography for decades to come.
Frequently Asked Questions
1. How many children are there in the world?
Using the under-18 definition, approximately 2.3 to 2.4 billion people, or 29.4 percent of the world’s population, were under age 18 as of 2024, according to U.S. Census Bureau estimates. Using the narrower under-15 definition, the figure is approximately 1.8 billion.
2. What percentage of the world’s population is under 15?
Roughly 22 to 23 percent of the world’s population was under age 15 in the early 2020s, according to UN Statistics Division data, though this share is projected to begin declining slowly starting around 2025.
3. Which countries have the most children as a share of population?
Niger leads globally at 56.7 percent of its population under age 18, followed closely by Somalia, Uganda, Mali, and Angola, all above 53 percent, according to 2024 U.S. Census Bureau international data.
4. Which countries have the smallest share of children?
Monaco has the lowest share of any country or territory tracked, at 11.7 percent under age 18, followed by South Korea at 13.3 percent and Bosnia and Herzegovina at 14.3 percent.
5. Where do most of the world’s children live geographically?
Asia is home to about 60 percent of the world’s children, and developing regions overall account for roughly 88 percent of the global child population, according to UN Statistics Division analysis.
6. Is the number of children in the world still growing?
Globally, the under-15 population grew from roughly 1.4 billion to 1.8 billion over recent decades but is projected to begin a slow decline starting around 2025, even as Africa’s child population continues growing for longer due to regional population momentum.
7. Why is Africa’s child population still rising while Asia’s is falling?
Africa’s fertility decline started later and has proceeded more slowly than Asia’s, and its population of women in reproductive ages is still growing, sustaining continued growth in the number of children even as the fertility rate per woman gradually falls.
8. What challenges come with a very high child population share?
Countries with high child shares face sustained pressure to expand education systems and child protection services; UNICEF reports about one in four of the world’s children under 18 have experienced disruptions to childhood through early marriage, early pregnancy, or exclusion from education.
9. How has child mortality affected the global child population?
Falling child mortality has increased the surviving global child population over time; UNICEF reports deaths of children under five fell from 9.8 million in 2000 to 5.4 million in more recent data, meaning more children now survive into the counted population.
10. Will the child population share keep falling everywhere?
Yes, but at very different speeds. UNICEF projects Africa’s child population share will fall to just under 40 percent by 2050, still far above the rest of the world, while East Asia and Western Europe, already at much lower shares, are projected to continue declining further from their already-reduced 2024 levels.
Sources
- U.S. Census Bureau, Vintage 2024 Population Estimates and November 2024 International Database Release
- United Nations Statistics Division, The World’s Women 2020: Trends and Statistics
- UNICEF, The State of the World’s Children 2024: The Future of Childhood in a Changing World
- UNICEF, “Child Brides in Africa” data release and related reporting
- World Bank, World Development Indicators, Population Ages 0-14
