World Population clock statistics: sources and methodology
The world population counter displayed on Worldometers is based on analysis of data from two major sources: the United Nations and the U.S. Census Bureau.
- The United Nations Population Division of the Department of Economic and Social Affairs every two years calculates, updates, and publishes estimates of total population in its World Population Prospects series. These population estimates and projections provide the standard and consistent set of population figures that are used throughout the United Nations system.
The World Population Prospect: the 2008 Revision Database provides the most recent data available. Estimates and projected world and country specific populations are given from 1950 through 2050.
Data underlying the population estimates are national and sub national census data and data on births, deaths, and migrants available from national sources and publications, as well as from questionnaires. For all countries, census and registration data are evaluated and, if necessary, adjusted for incompleteness by the Population Division as part of its preparations of the official United Nations population estimates and projections.
- The International Programs Center at the U.S. Census Bureau, Population Division also develops estimates and projections based on analysis of available data (based on census, survey, and administrative information) on population, fertility, mortality, and migration for each country or area of the world.
For most countries adjustment of the data is necessary to correct for errors, omissions, and inconsistencies in the data. Finally, since most recent data for a single country is often at least two years old, the current world population figure is necessarily a projection of past data based on assumed trends. As new data become available, assumptions and data are reevaluated and past conclusions and current figures may be modified.
For information about how these estimates and projections are made by the U.S. Census Bureau, see the Population Estimates and Projections Methodology.
World Population at 6 billion and counting
The world population has reached 6 billion in 1999.
According to the United Nations the 6 billions figure was reached on October 12, 1999 (celebrated as the Day of 6 Billion) . According to the U.S. Census Bureau instead, it was reached on July 22, 1999, at about 3:49 AM GMT. Yet, according to the U.S. Census web site, the date and time of when 6 billion was reached will probably change because the already uncertain estimates are constantly being updated.
How fast is the world population growing?
Population in the world is currently growing at a rate of around 1.15 % per year. The average annual population change is currently estimated at over 77 million.
Annual growth rate reached its peak in the late 1960s, when it was at 2% and above. The rate of increase has therefore almost halved since its peak of 2.19 percent, which was reached in 1963, to the current 1.15%.
The annual growth rate is currently declining and is projected to continue to decline in the coming years, but the pace of the future change is uncertain (1). Currently, it is estimated that it will become less than 1% by 2020 and less than 0.5% by 2050.
This means that world population will continue to grow into the 21st century, but at a slower rate compared to the recent past. World population has doubled (100% increase) in 40 years from 1959 (3 billion) to 1999 (6 billion). It is now estimated that it will take a further 42 years to increase by another 50%, to become 9 billion by 2042.
United Nations projections (Pdf document) indicate that world population will nearly stabilize at just above 10 billion persons after 2200.
What was the population of the world in the past?
The chart above clearly illustrates how world population has changed in history. The US Census Bureau has assembled a table with estimated population from 10000 BC to 1950 according to different sources.
At the dawn of agriculture, about 8000 B.C., the population of the world was approximately 5 million. Over the 8,000-year period up to 1 A.D. it grew to 200 million (some estimate 300 million or even 600, suggesting how imprecise population estimates of early historical periods can be), with a growth rate of under 0.05% per year.
A tremendous change occurred with the industrial revolution: whereas it had taken all of human history until around 1800 for world population to reach one billion, the second billion was achieved in only 130 years (1930), the third billion in less than 30 years (1959), the fourth billion in 15 years (1974), and the fifth billion in only 13 years (1987). During the 20th century alone, the population in the world has grown from 1.65 billion to 6 billion.
| Year |
Population |
| 1 |
200 million |
| 1000 |
275 million |
| 1500 |
450 million |
| 1650 |
500 million |
| 1750 |
700 million |
| 1804 |
1 billion |
| 1850 |
1.2 billion |
| 1900 |
1.6 billion |
| 1927 |
2 billion |
| 1950 |
2.55 billion |
| 1955 |
2.8 billion |
| 1960 |
3 billion |
| 1965 |
3.3 billion |
| 1970 |
3.7 billion |
| 1975 |
4 billion |
| 1980 |
4.5 billion |
| 1985 |
4.85 billion |
| 1990 |
5.3 billion |
| 1995 |
5.7 billion |
| 1999 |
6 billion |
| 2000 |
6.1 billion |
| 2005 |
6.45 billion |
| 2006 |
6.5 billion |
| 2010 |
6.8 billion |
| 2020 |
7.6 billion |
| 2030 |
8.2 billion |
| 2040 |
8.8 billion |
| 2050 |
9.2 billion |
|
How is the population distributed around the world?
Refer to this population density map:
How many people have ever lived on earth?
It was written during the 1970s that 75% of the people who had ever been born were alive at that moment. This was grossly false.
Assuming that we start counting from about 50,000 B.C., the time when modern Homo sapiens appeared on the earth (and not from 700,000 B.C. when the ancestors of Homo sapiens appeared, or several million years ago when hominids were present), taking into account that all population data are a rough estimate, and assuming a constant growth rate applied to each period up to modern times, it has been estimated that a total of approximately 106 billion people have been born since the dawn of the human race, making the population currently alive roughly 6% of all people who have ever lived on planet Earth.
Others have estimated the number of human beings who have ever lived to be anywhere from 45 billion to 125 billion, with most estimates falling into the range of 90 to 110 billion humans.
