( CNN ) -- The world 's population is about to reach 7 billion on Monday , according to the United Nations . More than a third of the globe 's people are in two countries . China and India account for more than 1 billion people each . Both have at least three times as many people as the United States , which has the world 's third-largest population at a little more than 300 million . Visualize 7 billion at once . Indonesia and Brazil round out the top five , according to the most recent estimates from the CIA World Factbook . Twelve countries in the world have more than 100 million people . Eight of them are Asian countries . The other four are the U.S. , Brazil , Nigeria and Mexico . At the bottom of the list is Pitcairn Islands , with an estimated 48 people . The British territory is in the south Pacific . More Comparisons : Which countries are perceived to be the most corrupt ? Which country has the smallest gender gap ? Where is the Internet most popular ? Where are the undernourished ? Where do people live the longest ? Which countries have the most vacation days ? Who requires the most education ? Who 's got the highest ( and lowest ) unemployment rates ?
China and India are the world 's two most populous countries ; both have more than 1 billion people . The United States is a distant third with a little more than 300 million people . Last on the list : Pitcairn Islands , with an estimated 48 people .