In Monaco, half the population has already passed their mid-fifties. In Japan, the median resident is closer to 50 than 40. These are not outliers drifting slightly above the global average of roughly 31 years. They sit at nearly double it, the product of decades of low birth rates layered on top of some of the longest life expectancies ever recorded.
Population aging is not a distant forecast for these countries. It is the daily reality shaping their schools, hospitals, pension systems, and labor markets right now. Where the world’s youngest countries are still building schools fast enough to keep up with expanding child cohorts, the world’s oldest countries are doing the opposite: closing schools as birth cohorts shrink, while scrambling to expand elder care capacity for a rapidly growing retiree population. This piece ranks the world’s oldest populations, explains what put them there, and looks at what the same trajectory means for the dozens of countries following close behind.
Oldest Countries in the World
| Country | Median Age (approx.) | Share Aged 65+ (approx.) | Total Fertility Rate | Population (approx.) |
|---|---|---|---|---|
| Monaco | ~55 years | ~35% | ~1.5 children/woman | ~39,000 |
| Japan | ~49-50 years | ~30% | ~1.2 children/woman | ~124 million |
| Italy | ~48 years | ~24% | ~1.2 children/woman | ~59 million |
| San Marino | ~49 years | ~24% | ~1.1 children/woman | ~34,000 |
| Portugal | ~47 years | ~24% | ~1.4 children/woman | ~10 million |
| Germany | ~46 years | ~23% | ~1.5 children/woman | ~84 million |
| Greece | ~46 years | ~23% | ~1.3 children/woman | ~10 million |
| South Korea | ~45 years | ~19% | ~0.72 children/woman | ~52 million |
Figures are approximate, drawn from UN World Population Prospects 2024 data as compiled by CIA World Factbook, StatisticsTimes, and related trackers. Microstates such as Vatican City are frequently excluded from country rankings due to their extremely small, non-representative populations, even though Vatican City’s own median age is the highest recorded anywhere.
South Korea deserves particular attention on this list, not for its median age alone but for its fertility rate: at approximately 0.72 children per woman, it is the lowest total fertility rate ever recorded for a country of its size, roughly a third of the 2.1 children per woman needed for a population to replace itself without immigration. At that rate, demographers have noted that South Korea’s population could roughly halve within a generation if the trend does not reverse, a trajectory with few historical precedents among countries of its scale and economic importance. South Korea has also recorded more deaths than births for several consecutive years, meaning its population is now shrinking through natural decline alone, independent of any migration effects.
Why Countries Become Old
No single factor explains why a country ends up with a population this old. It is the compounding effect of several long-running trends operating together over multiple decades.
- Low fertility: every country on this list has a total fertility rate well below the 2.1 replacement threshold, several sitting at or near half that level.
- Longer life expectancy: these countries also rank among the highest in the world for life expectancy, extending the number of years each generation spends in the older age brackets.
- Declining mortality: falling death rates at every age, not just in old age, mean more people survive long enough to reach 65 and beyond in the first place.
- Migration of younger workers: in some of these countries, younger residents have emigrated for work or education, further tilting the remaining population toward older ages.
- Historical baby boom generations reaching retirement: several of these countries, including Germany, Italy, and Japan, experienced a mid-20th-century baby boom whose large cohorts are now moving into their retirement years, temporarily accelerating the aging process on top of the underlying low-fertility trend.
Regional Concentration of Aging
Population aging is heavily concentrated in a handful of regions rather than spread evenly around the world, mirroring, in reverse, the same regional concentration seen among the world’s youngest countries.
- Europe: Southern and parts of Eastern Europe post some of the highest median ages globally, including Italy, Portugal, Greece, and Spain, alongside microstates such as Monaco, San Marino, and Andorra.
- East Asia: Japan and South Korea rank among the world’s oldest populations, and China’s population, while still younger on average, is aging faster than almost any large country in history because its fertility decline was so rapid and so recent.
- North America: Canada and the United States are aging more slowly than Europe or East Asia but are still moving steadily above the global median age, driven by falling fertility and a large baby boom generation now retiring.
- Other rapidly aging regions: several Caribbean and small island territories also post surprisingly high median ages, often driven by outward migration of younger residents combined with long life expectancy among those who remain.
Economic Effects of Population Aging
The economic consequences of an aging population reach well beyond pension budgets, touching nearly every major lever of long-term growth.
- Workforce shortages: a shrinking working-age population relative to retirees is already constraining labor supply in Japan, Germany, and Italy, pushing some employers toward automation or expanded immigration to fill open roles.
- Pension costs: pay-as-you-go pension systems designed for a much younger population structure face mounting strain as the ratio of workers to retirees keeps falling, forcing difficult choices between higher contributions, reduced benefits, or later retirement ages.
- Healthcare spending: older populations require more chronic disease management, raising healthcare costs as a share of national budgets, a pressure already visible in countries such as Italy, where pension and healthcare spending together consume a large share of GDP.
- Savings and investment: aging populations tend to shift national savings patterns, with implications for long-term capital markets and public debt sustainability, since a larger retired population typically draws down savings rather than accumulating them.
- Productivity: some economists link aging workforces to slower productivity growth, though this effect varies considerably by country and by how well older workers are retained, retrained, and kept economically active.
- Automation: countries facing the steepest workforce declines, including Japan and Germany, have invested heavily in robotics and automation partly in direct response to shrinking labor supply, with Germany posting some of the highest industrial robot densities in Europe.
Social Effects
Beyond the economic ledger, an aging population reshapes daily life in ways that show up gradually but touch nearly every household.
- Family structures: smaller families and rising longevity mean more households now include fewer working-age adults supporting more older relatives, a shift sometimes described as the “sandwich generation” problem, where middle-aged adults care for both aging parents and their own children simultaneously.
- Elder care: demand for elder care services, from home health aides to residential facilities, is rising faster than supply in several of the fastest-aging countries, creating waiting lists and rising costs for families seeking care.
- Housing: aging populations shift housing demand toward accessible, smaller-footprint homes suited to older residents living independently longer, while also creating surplus stock in areas built for larger, younger families.
- Healthcare access: rural areas within aging countries often see healthcare access shrink first, as medical providers concentrate in larger population centers, leaving older residents in smaller towns with longer travel times for care.
- Intergenerational support: with fewer children per family, the traditional model of family-based elder care is under growing strain in many of these societies, pushing more of the caregiving burden onto formal institutions and public systems.
Can Immigration Reverse Population Aging?
Immigration can meaningfully slow population aging, but it cannot reverse the underlying trend on its own, a distinction that matters considerably for how governments plan around the issue.
- Role of migration: countries such as Germany and Canada have used immigration to offset some of the workforce contraction caused by low domestic fertility, adding younger working-age residents to the population and, in Germany’s case, accepting more migrants in recent years than any other European country.
- Limits of migration as a demographic solution: the scale of immigration required to meaningfully lower a country’s median age over the long run is far larger than most countries have shown political appetite or capacity to sustain, and immigrants themselves eventually age into the same older brackets, meaning migration delays rather than eliminates the underlying pressure.
- Integration and workforce participation: immigration only offsets aging effectively when new arrivals are integrated into the labor force at reasonably high participation rates, which depends heavily on language training, credential recognition, and labor market conditions, and integration challenges have complicated this approach in several European countries even as headline migration numbers have risen.
What Happens Next?
- Projected aging through 2050: the UN projects the global median age will reach roughly 37 years by 2050, and countries already at the top of today’s rankings are expected to age further still, pushing some national median ages toward the high 50s.
- Growth of the 80-plus population: the number of people aged 80 and older worldwide is projected to keep rising sharply, with the fastest growth concentrated in countries that are already among the oldest today, adding new strain to long-term care systems that are already stretched.
- Shrinking working-age populations: Japan, South Korea, Italy, and several Eastern European countries are projected to see their working-age populations shrink significantly over the coming decades absent a substantial rise in fertility or immigration, with some projections showing workforce declines measured in the millions over just a decade or two.
- Policy responses: governments across the world’s oldest countries are experimenting with a mix of pronatalist family benefits, extended retirement ages, expanded immigration programs, and automation investment, with mixed results so far in reversing the underlying trend, though some measures have succeeded in slowing the pace of decline.
Countries at the top of this ranking today are, in effect, a preview of where a much larger share of the world is headed. Fertility below replacement level is no longer confined to a handful of wealthy economies; more than half the global population now lives in a country with below-replacement fertility, according to the UN. Japan, Italy, and South Korea are not exceptions to the global pattern anymore. They are simply further along a path that a growing list of countries, including several major emerging economies, are now beginning to walk as well.
Frequently Asked Questions
1. Which country has the oldest population in the world?
Excluding microstates such as Vatican City, Monaco typically ranks highest, with a median age near 55 years, followed closely by Japan.
2. What is Japan’s median age?
Approximately 49 to 50 years, among the highest of any large country.
3. Which large country has the lowest fertility rate in the world?
South Korea, with a total fertility rate of approximately 0.72 children per woman, roughly a third of the replacement level.
4. Why are Southern European countries like Italy and Portugal aging so quickly?
A combination of long-term low fertility, high life expectancy, and, in some cases, outward migration of younger residents.
5. Can immigration solve population aging?
Immigration can slow the pace of aging and support the workforce, but it cannot fully reverse the underlying demographic trend on its own, since immigrants also age over time.
6. What is the global median age for comparison?
Approximately 31 years, roughly half the median age of the world’s oldest countries.
7. How does population aging affect pension systems?
It raises the ratio of retirees to working-age contributors, straining pay-as-you-go pension systems that were designed around much younger population structures.
8. Which region has the most countries with aging populations?
Europe, followed closely by East Asia, particularly Japan and South Korea.
9. Is China’s population aging quickly?
Yes. China’s fertility decline happened rapidly and relatively recently, meaning its population is aging faster than almost any other large country in history.
10. When will the global median age reach the level of today’s oldest countries?
Not this century under current UN projections. The global median age is expected to reach roughly 37 years by 2050, still well below the 45-to-55-year range of today’s oldest countries.
Sources
- United Nations, World Population Prospects 2024 Revision, Population Division, Department of Economic and Social Affairs
- CIA World Factbook, median age estimates, 2024
- StatisticsTimes.com and PopulationPyramids.org, median age by country compilations
- Visual Capitalist, “Map: The World’s Oldest and Youngest Countries, by Median Age”
- CEOWORLD Magazine, “Ranked: The Oldest and Youngest Countries in the World by Median Age”
- Helgi Library, “Which Country Has the Oldest Population?”
