The country with the largest population is – as you probably already guessed – China with (about) 1.371 billion (1 billion 371 million). It is followed by India with 1,311 billion, the United States with 321,4 million, Indonesia with 257,6 million, and Brazil with 207,8 million.
Given the fact that the total population of Earth is about 7,5 billion, these five countries account for 46% of the entire Earth’s population, that is, about half! (These figures are based on 2015 data)