One in six people will be over 65 by 2050
The 2024 edition of the UN World Population Prospects confirmed a demographic shift with no historical precedent: by 2050, the number of people aged 65 and older will exceed the number of children under five for the first time in human history. The implications stretch across every system that modern societies have built on the assumption of a young, growing population.
The scale of the shift
In 2024, roughly 10% of the world's population — about 800 million people — are aged 65 or older. By 2050 that number is projected to reach approximately 1.6 billion, representing around 1 in 6 people globally. The share over 80 is growing even faster: from roughly 200 million today to over 450 million by 2050, according to the UN WPP 2024 data booklet.
Ageing is driven by two forces acting simultaneously: falling fertility means fewer young people are being born, and rising life expectancy means older people live longer. The result is a shift in the population pyramid from the classic wide-base shape — many young, few old — toward a rectangular or even top-heavy structure. Our World in Data's age structure tracker lets you animate this transition by country.
Where ageing is most advanced
Japan is the world's oldest large country, with approximately 30% of its population already over 65 — a level most other countries will not reach until mid-century. Japan's Statistics Bureau updates the figures annually. Italy, Finland, Greece, Portugal, and Germany all exceed 23%. In these countries, the median age now exceeds 46 years.
China's ageing is accelerating rapidly, driven by decades of low fertility following the one-child policy. The National Bureau of Statistics of China reported that the working-age population (15–59) has been shrinking since 2011. By 2050, China's over-65 population is projected to reach around 400 million — roughly equal to the entire current US population.
By contrast, sub-Saharan Africa will remain relatively young through mid-century. The median age in Niger is currently about 15 years — compared to 49 in Japan. This contrast is the central demographic divergence of the 21st century and is directly visible when comparing ridgeline shapes in the PopulationTheGuide explorer.
Economic and social consequences
The most direct economic measure of ageing is the old-age dependency ratio — the number of people aged 65+ per 100 working-age adults (15–64). In 1950 the global old-age dependency ratio was about 8. By 2050 it is projected to reach 26 — more than three times higher. In Japan it is already above 50, and could approach 80 by mid-century. The OECD tracks pension system sustainability across member countries.
Pension systems across the developed world were designed with dependency ratios of 10–15 in mind. Most were built as pay-as-you-go structures: today's workers fund today's retirees. As the ratio shifts, the same level of pension income requires either higher contributions from workers, reduced benefits for retirees, higher retirement ages, or increased immigration of working-age people. The ILO's social security department publishes country-level analysis of these pressures.
Healthcare spending is the other major pressure point. Older populations use healthcare at significantly higher rates, and the types of care shift — from acute conditions toward chronic disease management, long-term care, and dementia. The WHO ageing and health fact sheet provides a summary of the projected care needs.
Ageing and population projections
Ageing does not simply mean fewer people — it means a different age distribution with profound implications for what kinds of economic activity are possible. Countries with shrinking working-age populations face structural constraints that cannot be resolved through productivity gains alone. Immigration is the main short-term lever: countries like Canada, Australia, and Germany have explicitly structured immigration policy around demographic needs.
In the UN's medium-variant projections, migration is treated as a separate input from fertility and mortality. Countries with persistent below-replacement fertility but substantial inflows — like the United States — maintain a younger age structure than pure domestic fertility would suggest. Those with both low fertility and low immigration — like South Korea and parts of Southern Europe — face the steepest ageing curves. The UN WPP projection tables break down each country's future trajectory by age group.
Frequently asked questions
What share of the world population is currently over 65?
As of 2024, approximately 10% of the global population — around 800 million people — are aged 65 or older. By 2050 that share is projected to reach 1 in 6, with around 1.6 billion over-65s, according to the UN WPP 2024.
Which regions are ageing fastest?
East Asia, Southern Europe, and Northern and Western Europe have the oldest populations today. Japan leads with around 30% over-65. China is ageing rapidly due to past low-fertility policy. Sub-Saharan Africa will remain relatively young through mid-century — see the contrast in median age data by country.
How does population ageing affect the economy?
Ageing raises the old-age dependency ratio — the number of retirees per working-age adult. Higher ratios strain pension systems, healthcare budgets, and labour supply. The OECD tracks policy responses across member countries.
Can immigration offset population ageing?
Immigration can slow ageing by adding working-age people, but the scale required to fully offset low fertility is politically and logistically large. Countries like Canada, Australia, and Germany use immigration explicitly to maintain demographic balance. Our World in Data's migration section examines the numbers across countries.