Guesstimates

Guesstimating the number of people ever born, then, requires selecting population sizes for different points from antiquity to the present and applying assumed birth rates to each period. We start at the very, very beginning—with just two people (a minimalist approach!).

One complicating factor is the pattern of population growth. Did it rise to some level and then fluctuate wildly in response to famines and changes in climate? Or did it grow at a constant rate from one point to another? We cannot know the answers to these questions, although paleontologists have produced a variety of theories. For the purposes of this exercise, it was assumed that a constant growth rate applied to each period up to modern times. Birth rates were set at 80 per 1,000 per year through 1 A.D. and at 60 per 1,000 from 2 A.D. to 1750. Rates then declined to the low 30s by the modern period.

This semi-scientific approach yields an estimate of about 108 billion births since the dawn of the human race. Clearly, the period 8000 B.C. to 1 A.D. is key to the magnitude of our number, but, unfortunately, little is known about that era. Some readers may disagree with some aspects—or perhaps nearly all aspects—of the table, but at least it offers one approach to this elusive issue. If we were to make any guess at all, it might be that our method underestimates the number of births to some degree. The assumption of constant population growth in the earlier period may underestimate the average population size at the time. And, of course, pushing the date of humanity's arrival on the planet before 50,000 B.C. would also raise the number, although perhaps not by terribly much.

So, our estimate here is that about 6.5 percent of all people ever born are alive today. That's actually a fairly large percentage when you think about it.

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 specie, 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.