This article lists current estimates of theworld population in history. In summary, estimates for the progression of world population since theLate Middle Ages are in the following ranges:

Estimates for pre-modern times are necessarily fraught with great uncertainties, and few of the published estimates haveconfidence intervals; in the absence of a straightforward means to assess the error of such estimates, a rough idea of expert consensus can be gained by comparing the values given in independent publications. Population estimates cannot be considered accurate to more than two decimal digits; for example, the world population for the year 2012 was estimated at 7.02, 7.06, and 7.08 billion by theUnited States Census Bureau, thePopulation Reference Bureau, and theUnited Nations Department of Economic and Social Affairs, respectively, corresponding to a spread of estimates of the order of 0.8%.

As a general rule, the confidence of estimates on historical world population decreases for the more distant past. Robust population data exist only for the last two or three centuries. Until the late 18th century, few governments had ever performed an accurate census. In many early attempts, such as inAncient Egypt and thePersian Empire, the focus was on counting merely a subset of the population for purposes of taxation or military service.^[2] Published estimates for the 1st century ("AD 1") suggest uncertainty of the order of 50% (estimates range between 150 and 330 million). Some estimates extend their timeline into deep prehistory, to "10,000 BCE", i.e., theearly Holocene, when world population estimates range roughly between 1 and 10 million (with an uncertainty of up to an order of magnitude).^[3][4]

Estimates for yet deeper prehistory, into thePaleolithic, are of a different nature. At this time, human populations consisted entirely of non-sedentaryhunter-gatherer populations, withanatomically modern humans existing alongsidearchaic human varieties, some of which are still ancestral to the modern human population due tointerbreeding with modern humans during theUpper Paleolithic. Estimates of the size of these populations are a topic ofpaleoanthropology. A late humanpopulation bottleneck is postulated by some scholars at approximately 70,000 years ago, during theToba catastrophe, whenHomo sapiens population may have dropped to as low as between 1,000 and 10,000 individuals.^[5][6] For the time of speciation ofHomo sapiens, some 200,000 years ago, aneffective population size of the order of 10,000 to 30,000 individuals has been estimated, with an actual "census population" of earlyHomo sapiens of roughly 100,000 to 300,000 individuals.^[7]

Estimates regarding the questions of "how many people have ever lived?" or "what percentage of people who have ever lived are alive today?" can be traced to the 1970s.^[8] The more dramatic phrasing of "the living outnumber the dead" also dates to the 1970s, a time ofpopulation explosion and growing fears ofhuman overpopulation in the wake ofdecolonization and before the adoption of China'sone-child policy. The claim that "the living outnumber the dead" was never accurate.Arthur C. Clarke in2001: A Space Odyssey (1968) has the claim that "Behind every man now alive stand 30 ghosts, for that is the ratio by which the dead outnumber the living", which was roughly accurate at the time of writing.^[9][10]

Recent estimates of the "total number of people who have ever lived" are in the order of 100 billion.^[10][11] The answer depends on the definition of "people", i.e., whether onlyHomo sapiens are to be counted, or all of the genusHomo; due to the small population sizes in theLower Paleolithic, however, the order of magnitude of the estimate is not affected by the choice of cut-off date substantially more than by the uncertainty of estimates throughout the Neolithic to Iron Age.^[12] Importantly, the estimate is also affected by the estimate ofinfant mortalities vs.stillborn infants, due to the very high rate of infant mortality throughout the pre-modern period. An estimate on the "total number of people who have ever lived" as of 1995 was calculated by Haub (1995) at "about 105 billion births since the dawn of the human race" with a cut-off date at 50,000 BC (beginning of the Upper Paleolithic), and inclusion of a high infant mortality rate throughout pre-modern history.^[13]

The following table usesastronomical year numbering for dates, negative numbers corresponding roughly to the corresponding year BCE (strictly speaking, for example, −8,000 = 8,001 BCE, etc.). The table starts counting approximately 10,000 years before present, or around 8,000 BCE, during the middleGreenlandian, about 1,700 years after the end of theYounger Dryas and 1,800 years before the8.2-kiloyear event.

From the beginning of theearly modern period until the 20th century, world population has been characterized by a rapid growth. For the period ofClassical antiquity to theMiddle Ages, roughly 500 BCE to CE 1500, there was also a general tendency of growth (estimated at a factor 4 to 5 over the 2,000-year period), but not strictlymonotonic: A noticeable dip in world population is assumed due to theBlack Death in the mid-14th century.^[14]

AfterWorld War II, demographic data of some accuracy becomes available for a significant number of countries, and population estimates are often given as grand totals of numbers (typically given by country) of widely diverging accuracies. Some sources give these numbers rounded to the nearest million or the nearest thousand, while others give them without any rounding.

Taking these numbers at face value would befalse precision; in spite of being stated to four, seven, or even ten digits, they should not be interpreted as accurate to more than three digits at best (estimates by theUnited States Census Bureau and by theUnited Nations differ by about 0.5–1.5%).

The regional makeup of the world's has changed dramatically in the past two thousand years. In 1 CE, population in Asia was more than 4 times the European population,^[18] and the combined population of Sub-Saharan Africa and Latin America totaled roughly 6 percent of the world's population. The total population of the "Western Offshoots"--the former British colonies of Canada, Australia, New Zealand, and the United States--made up less than 0.5% of the total. The distribution of population by region in 2022 looks very different: Latin America and Sub-Saharan Africa are home to nearly a quarter of the people in the world, and more than 5% live in the four "Western Offshoots" nations.

The rate of growth of the world's population changed dramatically as well, rising more than a hundred-fold from an average population growth of less than a tenth of a percent per year from 1-1000 CE to 1.9% average annual growth between 1950 and 1975. Growth has slowed substantially in the years since, averaging 1.1% annual growth between 2000 and 2022.

The historical population for many countries in the world is difficult to estimate before the past several hundred years due to incomplete recordkeeping or insufficient archaeological evidence. However, theMaddison Project has been able to estimate the populations of 43 countries back to 1 CE. They show that the two countries with the largest populations in 2022, India and China, were also the world's most populous countries more than two thousand years ago. Western European populations generally grew slowly until the late 18th century, when theIndustrial Revolution caused both standards of living and populations to rise rapidly.

• Haub, Carl (October 2011)."How Many People Have Ever Lived on Earth?".Population Reference Bureau. Archived fromthe original on 24 April 2013. Retrieved21 July 2013.
• "Human population numbers as a function of food supply"(PDF).Russel Hopfenburg, David Pimentel, Duke University, Durham, NC; Cornell University, Ithaca, NY.
• Guinnane, Timothy W. (2023)."We Do Not Know the Population of Every Country in the World for the Past Two Thousand Years".The Journal of Economic History.83 (3):912–938.doi:10.1017/S0022050723000293.

• Historical Estimates of World Population –United States Census Bureau

• World population
• Demographic history

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