According to a Pew estimation in 2025, Christians made up to 2.3 billion of the worldwide population of about 8 billion people. This represents nearly one-third of the world's population and is the largest religion in the world, with the three largest groups of Christians being the Catholic Church, Protestantism, and the Eastern Orthodox Church. The largest Christian denomination is the Catholic Church, with 1.3 billion baptized members. The second largest Christian branch is either Protestantism (if it is considered a single group), or the Eastern Orthodox Church (if Protestants are considered to be divided into multiple denominations).
According to a 2020 Pew Research Center study, of the then 201 countries and territories, 120 had Christian majorities, four fewer than in the 2010 study.