Belgium Population

Belgium has below-replacement fertility and depends on immigration for its continued growth, in one of Europe's more densely populated and urbanised countries. Ageing is advancing steadily, with the usual pressures on pensions and care. Its demographics mirror the wider pattern of wealthy, low-birth, migration-sustained Europe.

With roughly 11.8 million people as of 2026, Belgium ranks 83rd in the world by population. A country of Western Europe, its trajectory to 2100 is governed by how births, deaths and migration play out. Population density stands at about 389 people for every square kilometre of land.

Growth continues for Belgium until around 2045, the year its population is set to crest at about 11.9 million. From there a slow fall takes it to roughly 11.1 million by century's end.

Fertility sits at about 1.38 births per woman, below the replacement level of roughly 2.1, so without migration the population would eventually shrink. Immigration is a meaningful contributor, bringing in more people than leave in a typical year.

Half of Belgium is currently younger than about 42, but by 2100 the median age is projected to reach around 49, even as life expectancy improves from about 82 years. A rising median age means fewer working-age people supporting each retiree over time.

The trajectory above is the UN's medium scenario. Wars, policy shifts, economic change and migration can all move the numbers, but the broad shape, growth followed by an eventual peak, is robust across the main variants.