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 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 further apart the variants get, which is why we show the low–high band rather than a single line alone.

That band is not a confidence interval. It is the span between two named fertility assumptions, so it carries no probability: it is not an 80% or a 95% range, and there is no claim that the outcome falls inside it. The UN does publish a genuinely probabilistic projection with statistical intervals, and we do not use it, so you will not see one quoted here. When we say a figure is uncertain we mean the assumptions could be wrong, not that we have measured how likely that is.

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.

Thresholds and milestone dates

A threshold crossing (8 billion, 100 million, and so on) is an event inside a year, not a year. Because the source publishes one value per year, we find the crossing by interpolating between the two 1 January values that straddle it, using the same arithmetic as the live counter. So a milestone date and the counter can never contradict each other.

This matters more than it sounds. Reading a milestone off the annual table by taking the first 1 January above the mark gives an answer that is up to a full year late, and always late, because the threshold was already passed when that year opened. On the 2024 revision the world crossed 8 billion during 2022, not 2023. We work that example through in full, including why the UN’s widely cited 15 November 2022 date differs.

Peaks and plateaus

A peak is the year a projected population is highest across 1950–2100, and a country has “already peaked” when that year is in the past. But a single year overstates what the data resolves. World population stays within 0.1% of its maximum from 2080 to 2088, and the years either side of the highest one differ from it by about half a million people in a total above ten billion. Where that band is wider than a year we report the band, and name the single highest year separately.

A related trap: a maximum in 2100 is the end of the projection, not a peak. 76 countries, including United States, Pakistan, Nigeria and Ethiopia, are still growing when the data runs out. We label those “still growing” rather than giving them a peak year, because the dataset contains no turning point for them.

Crossovers

Our “overtake” pages find 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. Both countries are read from the same variant and the same reference date, so a crossing is a like-for-like comparison. As with thresholds, the annual series gives the year of the crossing rather than an exact date.

Which files, and when they were processed

Population figures come from TPopulation1Jan in the WPP 2024 demographic indicators files, published in thousands and converted here to whole people. Every displayed metric is mapped to its exact source field in the data contract, along with the transformation applied to it.

We import a revision by hand and rebuild the site. Nothing on this site fetches anything from the UN at page load, and a new UN revision does not appear here on its own. The dataset revision currently in use, and the revision currently in use is UN World Population Prospects 2024, processed on 2026-06-15; the same pair is shown on the live counter and on sources.

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.