World population history

The Population Reference Bureau estimates that about 117 billion members of our species have ever been born. Our World in Data puts the total at around 108 billion, so the figure depends on the assumptions used.

No demographic data exist for more than 99% of the span of human existence, so every estimate of the total is built on assumptions about earlier populations.

The estimate rests on three things: how long humans have existed, the average size of the population in each period, and the number of births per 1,000 people in each period. It does not depend on the number of deaths.

The Population Reference Bureau takes modern Homo sapiens to have appeared around 190,000 BCE, and assumes a birth rate of 80 per 1,000 people each year through 1 CE and 60 per 1,000 from then to 1750.

Counting from 190,000 BCE, the 8 billion people alive in 2022 made up nearly 7% of everyone ever born, by the Population Reference Bureau's estimate. Our World in Data gives 6.5%.

Around 8000 BCE the world population was approximately 5 million, according to the Population Reference Bureau's rough averages of United Nations and other estimates.

Our World in Data states that as recently as 12,000 years ago there were only 4 million people worldwide, and that for most of human history the population was well under one million.

From about 5 million in 8000 BCE to about 300 million in 1 CE, the population grew at an average of only 0.05% a year.

The table puts the number of people born by 1 CE at about 55 billion, nearly half of the 117 billion total.

The estimated world population was 450 million in 1200 and 500 million in 1650, so it grew by only about 50 million over those 450 years.

The world population passed one billion in the early 1800s.

It took about another century to reach 2 billion. Since then it has quadrupled to eight billion.

The Population Reference Bureau's table puts the world at about 2.5 billion in 1950 and about 6.1 billion in 2000.

World Population Day, observed on 11 July, marks the date in 1987 when the world's population hit the 5 billion mark.

It took the global population 12 years to grow from 7 to 8 billion.

The United Nations links the rise to a gradual increase in human lifespan from improvements in public health, nutrition, personal hygiene and medicine, along with high fertility in some countries.

The United Nations marked 15 November 2022 as the day the world's population reached 8 billion people.

The US Census Bureau uses its own International Database and dates the 8 billion mark to 2023, a year later than the United Nations.

The United Nations expects 9 billion in about 15 years from 2022, around 2037. The Census Bureau projects 9 billion by 2039.

As of 2024, China and India were the two most populous countries, with about 1.4 billion people each.

The United Nations projects that the world population will peak at approximately 10.3 billion in the mid-2080s, then fall gradually to around 10.2 billion by 2100.

The Census Bureau projects a later and higher peak of 10.6 billion in 2092, which shows how sensitive projections are to assumptions about births and deaths.

The global fertility rate was 2.3 live births per woman as of 2024, which is one child fewer than in 1990.

As of 2024, one in four people lived in a country where the population has already peaked.

The population of sub-Saharan Africa is projected to rise by 79% to 2.2 billion by 2054, according to the United Nations.