Thailand Population

Thailand has one of the lowest fertility rates in the developing world, having fallen well below replacement despite incomes that remain middle-tier. As a result it is ageing faster than almost any country at its income level, a clear case of growing old before growing rich. The pool of young workers is already shrinking, posing hard questions for its economy and its system of care.

Thailand is home to about 71.6 million people in 2026, the 20th largest population of any country. Set in South-Eastern Asia, its demographic path this century turns on the balance of births, deaths and migration. It packs in roughly 140 people per square kilometre.

The peak is already behind Thailand: its population maxed out at about 71.8 million near 2022 and is contracting. By 2050 the UN expects around 66.6 million people, and by 2100 about 45.7 million. The 50 million threshold was crossed near 1986.

At about 1.20 births per woman, Thailand has one of the world's lowest fertility rates, well under the replacement level of around 2.1.

The median age is set to climb from about 40 today to roughly 52 by 2100, while life expectancy, near 77 years, keeps rising. That ageing slowly changes everything from the size of the workforce to the cost of care and pensions.

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, a population already past its peak, is robust across the main variants.