A new report by the US-based Pew Research Center has revealed that Islam is currently the fastest-growing religion worldwide, while Christianity is witnessing a marked decline—particularly in developed regions such as Europe, North America, Australia, and New Zealand.
According to the findings, for every individual born into Christianity, three others are leaving the faith. If these demographic and religious trends continue, Islam is projected to surpass Christianity as the world’s largest religion in the coming decades.
Between 2010 and 2020, the global Muslim population grew by 347 million—an increase greater than that of all other religions combined. This surge is largely attributed to natural population growth, as Muslims tend to have higher birth rates and a younger median age than adherents of other religions. Religious conversion played only a minor role in this growth.
Despite the overall number of Christians rising from 1.22 billion to 2.3 billion, their share of the global population declined by 1.8%. This drop was most prominent in developed countries, where increased education levels and socio-economic development have contributed to a significant decline in religious affiliation, particularly among younger generations.
The number of people identifying as religiously unaffiliated has also increased notably. In 2020, 24.2% of the global population identified as non-religious—up from 23.3% in 2010. In North America, over 30% of the population now claims no religious affiliation. The largest populations of the unaffiliated are found in China (1.3 billion), the United States (101 million), and Japan (73 million).
Buddhism was the only major religion to experience a decline during this period, losing 19 million adherents—primarily due to rising secularism in East Asia.
Islam’s share of the global population rose by 1.8%, reaching 25.6% in 2020. Its sustained growth is driven by a younger demographic (average age 24), high fertility rates, and minimal rates of religious switching.
If these trends continue, Pew Research projects that the global Muslim and Christian populations will soon be nearly equal in size, with Islam potentially becoming the world’s largest religion within the next few decades.
