The old world.
Half of humanity is older than the median age, half younger — and that middle has moved: 22.2 years in 1950, 30.4 in 2023. The world got eight years older in seventy-three. Behind the world line the countries have flown apart: Japan's median was 21.3 in 1950 — younger than the world is today — and is 49.0 now, while Nigeria's went the other way, 18.1 to 17.8: a country that got younger over the whole record. The file carries the UN's projection to 2100 in a separate column, and this page keeps the separation: everything past the 2024 seam is drawn dashed and labeled a forecast — a record and a forecast never wear the same line. Every figure is computed from the records at render time.
published 2026-08-29 · estimates 1950–2023 · projection to 2100, drawn as such · edition 1 — updated only by a new dated edition · source: UN World Population Prospects via OWID
Eight years older in seventy-three.
The world's median age, 1950 to 2023 — and then the UN's projection, carried to 2100. The solid line is the record; the dashed line is a forecast, and the seam between them is marked on the exhibit — this page never lets the two trade clothes.
The countries flew apart.
Ten countries' medians over the estimate years — no projections here. South Korea aged 26.8 years in seventy-three (17.7 → 44.5), the fastest climb on the board; China passed the United States in 2019 — by three hundredths of a year, and the gap has widened every year since; and at the bottom, Nigeria ends the record younger than it began.
A 45-year gap between countries.
The record's own extremes in 2023, uncurated: the ten youngest and ten oldest of the file's 247 entities. Central African Republic at 14.3; Vatican at 59.6. Half of one country is children; half of another is past retirement — the same year, the same planet, the same column.
Whose numbers, and what this page refuses.
Whose numbers. Every figure is the UN World Population Prospects, as Our World in Data publishes it — the Median age column for the past, the Median age (Projected) column for the future. They are two columns in the file, and they stay two things on this page: solid and dashed, record and forecast, with the seam marked where the file itself switches.
The projection discipline. The forecast is drawn because the file carries it and readers will ask — but it appears in exactly one exhibit, dashed, labeled at the line, and never inside a sentence that states a fact. No finding on this page rests on a projected value. The world "reaching 42.1 by 2100" is the UN's forecast, and the one place those words appear is this paragraph, so labeled.
What this page refuses. No cause is attributed: median age is an outcome of fertility, mortality and migration histories, and this page draws the outcome without adjudicating the inputs. The extremes ladder is uncurated — dropping the Vatican or Monaco for being small would be an editorial cut dressed as a rule, so the record's own ranking stands and the caption says who is in it. And the China–United States crossing is stated as 2019 because the two series say so, not because a narrative does.