Growing religion

There are several different religions claiming to be the “fastest growing religion”. Such claims vary because of different definitions of “fastest growing”, and whether the claim is worldwide or regional. There are also many unreliable claims and rumors, especially for conversion rates, that often spread as urban legends.

Different definitions of “fastest growing”

Religions can grow in numbers because of conversion or because of higher birth rates in a religious group (assuming that children take on the religion of their parents). Religions in particular countries can grow because of immigration. So the fastest growing religion could refer to:

  • The religion whose absolute number of adherents is growing the fastest (by whatever means).
  • The religion that is growing fastest in terms of percentage growth per year (by whatever means).
  • The religion that is gaining the greatest number of converts.
  • The religion that is gaining the greatest number of associative members (those associating themselves via survey, effectively a popularity vote)

Measures counting absolute numbers tend to favour the larger religions; measures counting percentage growth the smaller ones. For example, if a religion had only 10 followers, a single addition would be a 10% increase, and would therefore dwarf the percentage growth rates of the larger religions.

The difficulty of gathering data

Statistics on religious adherence are difficult to gather and often contradictory; statistics for the change of religious adherence are even more so, requiring multiple surveys separated by many years using the same data gathering rules. This has only been achieved in rare cases, and then only for a particular country, such as the American Religious Identification Survey[1] in the USA, or census data from Australia[2] (which has included a voluntary religious question since 1911). Worldwide data are more difficult to gather than data on a particular country.

Statistics for rates of conversion are the most difficult to gather and the least reliable: they are often distorted by social taboos such as the ban on apostasy in Islam, sometimes amplified by governments and policies at social institutions like universities[3][4] or the reporting of commitments where the individual does not persist. This means that a lot of the data on growth of religions is derived from birth and immigration rates.

There are a large number of people who self-identify themselves as associated to a specific religion, but who are not religiously active. If, for example, asked to choose between Christianity and other religions they would say they were Christians; if asked to choose between Christianity, other religions and “Not religious”, they would say “Not religious”. This may make categorization difficult.

In countries with mandatory religions, official statistics will only reflect the official position of the government.

Claims to be the fastest growing religion

Note that it would be an argumentum ad populum fallacy to claim that being the “fastest growing religion” has any logical consequences about the truth of that religion.

Whilst it is possible to find claims that almost any religion is the fastest growing, it is much harder to find ones backed up by scientific data. A selection of the more credible claims are given below, but even these are often contradictory, and most of them only cover a limited period time or a single region of the world.


The Australian Bureau of Statistics through statistical analysis held Buddhism to be the fastest growing spiritual tradition/religion in Australia in terms of percentage gain with a growth of 79.1% for the period 1996 to 2001 (200,000→358,000).[5]


See also: Christian population growth

Globally, The World Christian Database as of 2007 estimated the growth rate of Christianity at 1.38%. High birth rates and conversions in the Southern Hemisphere were cited as the main reasons for the increase.[6]

Pentecostalism, described by the Pew Forum on Religion and Public Life as a group of charismatic movements,[7] has grown, according to researchers, from 72 million in 1995 to 525 million in 2000, though some have criticized these numbers as defining Pentecostalism too broadly.[8] According to a 2005 paper submitted to a meeting of theAmerican Political Science Association, most of this growth has occurred in non-Western countries and concludes the movement is the fastest growing religion worldwide.[8]

In Vietnam, the US Department of State estimates that Protestants in Vietnam may have grown 600% over the last decade in Vietnam.[9] In Nigeria, the numbers of Christians has grown from 21.4% in 1953 to 48.2% in 2003. In South Africa, Pentecostalism has grown from 0.2% in 1951 to 7.6% in 2001. In South Korea, Christianity has grown from 20.7% in 1985 to 29.2% in 2005 according to the Pew Forum.[10][11]


The 2001 American Religious Identification Survey (ARIS) survey, which involved 50,000 participants, reported that the number of participants in the survey identifying themselves as deists grew at the rate of 717 percent between 1990 and 2001. If this were generalized to the US population as a whole, it would make deism the fastest-growing religious classification in the US for that period, with the reported total of 49,000 self-identified adherents representing about 0.02% of the US population at the time.[12][13]

Falun Gong

No reliable data are available for the number of adherents of Falun Gong but as this religion was only established in 1992 most of the growth must have been by conversion. Estimates for the number of adherents for 1999 range from 2 million[14] to 100 million.[15]

Haredi Judaism

If Haredi Judaism is regarded as a separate religion from mainstream Judaism, then it is the fastest growing religion in the world by percentage growth per year. In Israel, Haredi Jews grow at a rate of 6% per year or a doubling time of about 11.5 years [16], mainly because of sustained high fertility levels. However, the current total population of Haredi Jews is around 1.3 million globally[17].


Further information: Demographics of India

Some 80% of the population of the Republic of India are Hindus, accounting for about 90% of Hindus worldwide. Their 10-year growth rate is estimated at 20% (based on the period 1991 to 2001), corresponding to a yearly growth close to 2% or a doubling time of about 38 years.[18]


Data for Islam reveal that the growing number of Muslims is due primarily to immigration (in Western Europe) and higher birth rates (worldwide).[19]

  • The “Pew Forum on Religion & Public Life” stated
Islam is already the fastest-growing religion in Europe. Driven by immigration and high birthrates, the number of Muslims on the continent has tripled in the last 30 years. Most demographers forecast a similar or even higher rate of growth in the coming decades.[20]


  • The American Religious Identification Survey gives Wicca an average annual growth of 143% / 11,454 for the period 1990 to 2001 (8,000→134,000 – U.S. data / similar for Canada & Australia).[1][21]


  • The American Religious Identification Survey gave Non-Religious groups the largest gain in terms of absolute numbers – 14,300,000 (8.4% of the population) to 29,400,000 (14.1% of the population) for the period 1990 to 2001 in the USA.[1][21]
  • In Australia, census data from the Australian Bureau of Statistics give “no religion” the largest gains in absolute numbers over the 15 years from 1991 to 2006. from 2,948,888 (18.2% of the population that answered the question) to 3,706,555 (21.0% of the population that answered the question).[22]

World Christian Database

The World Christian Database (WCD) and its predecessor the World Christian Encyclopedia contains large amounts of data on numbers and growths of religions. It is used as a source for many web and newspaper articles. The following is a tabulation of their results: (Note: The annual growth in the world population over the same period is 1.41%.)

1970-1985[23] 1990-2000[24] 2000-2005[6]
3.65% – Bahá’í Faith 2.65% – Zoroastrianism 1.84% – Islam
2.74% – Islam 2.28% – Bahá’í Faith 1.70% – Bahá’í Faith
2.30% – Hinduism 2.13% – Islam 1.62% – Sikhism
1.67% – Buddhism 1.87% – Sikhism 1.57% – Jainism
1.64% – Christianity 1.69% – Hinduism 1.52% – Hinduism
1.09% – Judaism 1.36% – Christianity 1.38% – Christianity
1.09% – Buddhism
0.91% – Judaism


2000 Projected 2025 Projected 2050 50 Year Projected Growth 2000-2050
Religion + % + % + % New Adhereents % Growth
Christianity 1,999,563,838 33.0% 2,616,670,052 33.4% 3,051,564,342 34.3% 1,052,000,504 52.61%
Islam 1,188,242,789 19.6% 1,784,875,653 22.8% 2,229,281,610 25.0% 1,041,038,821 87.61%

The Carnegie Endowment for International Peace using the 2000-2005 edition of the World Christian Database, concluded that high birth rates were the reason for the growth in all six; however, the growth of Christianity was also attributed to conversions.[6] Although the World Christian Database does not cite sources, a review examining the reliability and bias of the WCD found it “highly correlated with other sources of data” but “consistently gave a higher estimate for percent Christian.” The Journal for the Scientific Study of Religion said that “on the whole we find that the WCD is reliable.”