Methodology

Every figure on populationclock.org is derived from the United Nations World Population Prospects 2024 (WPP 2024), the standard source for global demographic estimates and projections. We do not produce our own forecasts; we process, visualise and explain the UN’s.

The variants

The UN does not publish a single prediction. Instead it publishes several variants built on different assumptions, mainly about future fertility:

• Medium: the central scenario, and the default shown across this site.
• Low and High: fertility roughly half a child below and above the medium path. These form the shaded uncertainty band on country charts.

The medium variant is the most widely cited, but it is a scenario, not a promise. The further into the future a projection runs, the wider the plausible range becomes, which is why we show the low–high band rather than a single line alone.

The live counter

The UN publishes population “as of 1 January” for each year. Our live counter takes the value for 1 January of the current year and the following year, and interpolates smoothly between them based on how far through the calendar year we are. It is therefore an estimate of the current population consistent with the medium projection, not a real-time census. Births and deaths “this year” are the annual totals distributed evenly across the year in the same way.

Peaks, crossovers and thresholds

A country’s peak is simply the year its projected population is highest across 1950–2100. A country is “already peaked” if that year is in the past. Crossovers (our “overtake” pages) are detected by finding the year one country’s population first rises above another’s and stays above it through 2100; we deliberately ignore brief, non-durable crossings to avoid noise. Threshold years (when a country passes 100 million, 500 million, and so on) are read directly off the medium series.

Units and rounding

The UN publishes population in thousands; we convert to whole people. Throughout the site we round for readability: “1.44 billion”, not a false-precision figure down to the last person. Treat every projected number as a central estimate within a range, never an exact count.

What this site is not

These are demographic projections, not predictions of the future. Wars, pandemics, policy changes and migration shocks can and do move the numbers. The value of the projections is in the shape of the century (a slowdown, an eventual peak, a shift toward Africa), which is robust across the main variants, rather than in any single year’s figure.