This article lists estimates of world population over the course of history and prehistory, as well as projections of future developments.In summary, estimates for the progression of world population since the late medieval period are in the following ranges:Estimates for pre-modern times are necessarily fraught with great uncertainties, and few of the published estimates have confidence 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.