How Many People Have Ever Lived on Earth?

The question of how many people have ever lived on Earth is a perennial one among information calls to PRB. One reason the question keeps coming up is that somewhere, at some time back in the 1970s, a now-forgotten writer made the statement that 75 percent of the people who had ever been born were alive at that moment. This factoid has had a long shelf life, even though a bit of reflection would show how unlikely it is.

For this "estimate" to be true would mean either that births in the 20th century far, far outnumbered those in the past or that there were an extraordinary number of extremely old people living in the 1970s. But if we judge the idea that three-fourths of people who ever lived are alive today to be a ridiculous statement, have demographers come up with a better estimate? What might be a reasonable estimate of the actual percentage? In this video, PRB senior visiting scholar Carl Haub, with some speculation concerning prehistoric populations, approaches a guesstimate of this elusive number.