Director of the UN Population Division Hania Zlotnik said that there have been no big changes from the previous estimate in 2006.
"We are still projecting that by 2050 the population of the world will be around 9.1 billion," she said at a news conference on Wednesday, Mar 11.
"The projections are based on the assumption that fertility that is now around 2.56 children per woman is going to decline to about 2.02 children per woman in the world."
According to the data most of the additional 2.3 billion people will swell the population of the developing world, estimated to soar from 5.6 billion this year to 7.9 billion in 2050, and to spread among the 15-59 age group (1.2 billion) and those 60 or over (1.1 billion).
According to the study, the largest number of migrants will head to the United States — an estimated 1.1 million every year between 2010 and 2050.