Median age
The age that splits a population exactly in half: younger on one side, older on the other.
In short
Median age summarises a whole age structure, like the one behind dependency ratio, into a single number without needing to see the full shape.
How it's calculated
List everyone in a population from youngest to oldest and find the age of the person exactly in the middle. In practice this comes from age-structure estimates, not a literal list. The UN and national statistical agencies produce these estimates from census data, vital registration, and modelled interpolation.
Note Median age is not the same as average age. A small number of very old outliers can pull an average up without changing where the actual midpoint falls.
Typical values
Why it matters here
Median age is a shorthand for the same age structure that drives dependency ratio and reflects the long-run pattern in total fertility rate and life expectancy. A country's median age is a quick way to guess whether its ridgeline still has room to keep rising, or is closer to levelling off.
In 1950 the global median age was about 24. By 2023 it had risen to around 31, and the UN projects it to reach roughly 41 by 2100 under the medium-variant scenario. That shift of 17 years over 150 years is one of the most consequential structural changes in human history — a world where the average person is in middle age rather than youth, with profound implications for labour markets, healthcare, and social spending. Country and regional median age projections are downloadable from the UN World Population Prospects.
What rising median age tells us
A rising median age is the inevitable result of sustained low fertility and improving survival. It does not by itself signal economic decline — many of the world's most productive economies have high median ages — but it does signal that the composition of the workforce and the demands on social systems are changing. Countries where median age is rising fastest, like Japan, South Korea, and parts of Southern and Eastern Europe, are the laboratories for policies the rest of the world will eventually need: later retirement, higher labour productivity, managed immigration, and redesigned pension systems.
Frequently asked questions
What is median age of a population?
Median age is the age that divides a population exactly in half: half the people are younger, half are older. It is calculated from a population's age distribution and provides a single number that summarises whether a country's population is relatively young or old. Our World in Data's age structure charts show median age over time by country alongside population pyramids.
How does median age differ from average age?
Average (mean) age adds all ages together and divides by the total population. Median age simply finds the midpoint. Because a small number of very old people can skew the average upward, the median is often considered a more representative measure of a population's typical age.
Which countries have the highest and lowest median ages?
Japan and several European countries such as Germany and Italy have the world's highest median ages, typically above 45. Countries in sub-Saharan Africa — including Niger, Mali, and Chad — have the lowest, often below 16, reflecting very high fertility and young age structures. Current and projected median age data by country is available from the UN World Population Prospects.
Why does median age matter for economic growth?
A country's median age is closely linked to its dependency ratio and workforce size. A young median age can signal a coming demographic dividend if fertility is falling. A very high median age signals a shrinking workforce and rising pension and healthcare costs, which tend to weigh on long-run economic growth. The IMF's research on demographics covers the macroeconomic effects of ageing in detail.