Islam was the fastest-growing major religion worldwide from 2010 to 2020 in Pew Research Center’s comparison, published in 2025. The estimated Muslim population grew by about 21%, adding 347 million people and reaching about 2 billion. The worldwide rate answers a specific question about those ten years. A second question is where the increase happened. North America had the fastest percentage growth in its Muslim population among the regions Pew compared, while Asia and the Pacific remained home to most of the world’s Muslims. Pew Research Center’s 2010–2020 global comparison Pew Research Center’s Muslim population chapter
How the same population can have three growth figures
The increase of 347 million counts the people added to the global estimate. The 21% figure compares that increase with the estimated Muslim population at the beginning of the decade. A third measure uses everyone in the world as the denominator. On that measure, the Muslim share rose by 1.8 percentage points to 25.6%. Each figure describes a different relationship. A percentage rate makes it easier to compare groups that start at different sizes. The number added shows the scale of the increase. Pew Research Center’s 2010–2020 global comparison Pew Research Center’s Muslim population chapter
The distinction also explains how Christians could increase in number by 122 million while their share of the world population declined. The total number of people in the world grew faster than the Christian population in the period. Conversely, a group can have a large relative increase within a region while remaining a small share of that region’s residents. A headline about the fastest rate gives only one of those pieces of information. Pew Research Center’s 2010–2020 global comparison Pew Research Center’s Muslim population chapter
Where growth was fastest and where most Muslims lived
Pew estimated that the Muslim population of North America reached 5.9 million in 2020, up 52% over the decade. In sub-Saharan Africa it reached 369 million, up 34%. A 34% increase from the larger starting population in sub-Saharan Africa added many more people than a 52% increase from the smaller North American base. Pew estimated that Muslims were 1.6% of North America’s residents in 2020 and roughly a third of sub-Saharan Africa’s residents. Pew Research Center’s Muslim population chapter Pew Research Center on drivers of change
The Asia-Pacific region was home to about 59% of the world’s Muslims in 2020. Pew estimated that Indonesia had roughly 240 million Muslim residents, while India had about 213 million. Muslims made up about 15% of India’s residents. India can therefore rank among the countries with the largest Muslim populations while Muslims remain a minority there. The share of the world’s Muslims who live somewhere and the share of that place’s residents who are Muslim use different denominators. Pew Research Center’s Muslim population chapter
Why migration matters at one scale and births at another
Moving between countries changes where a person is counted. The move itself does not add to the worldwide count of people with that affiliation. Pew identified migration as an important contributor to Muslim population growth in North America and Europe. At the global scale, it attributed most Muslim population growth to demographics, particularly a younger age structure and higher average fertility. Its analysis of adults’ childhood and current affiliations found that people entering and leaving Islam broadly offset one another globally. That leaves room for individual conversions and regional differences. Pew Research Center on drivers of change
Canada offers a national example from a separate dataset and a longer period. Statistics Canada reported about 580,000 people identifying as Muslim in 2001 and about 1.78 million in 2021. The national share rose from 2.0% to 4.9%. In the 2021 census, about 19% of immigrants admitted from 2011 to 2021 reported being Muslim. About 30% of Canada’s Muslim population was born in Canada. The two statistics refer to different groups of people. Together they show why an account of Canada’s Muslim population needs to consider both migration and people born in the country. The median age of Muslims in the census was 30, compared with 41.2 for Canada as a whole. That figure describes the age distribution at one point in time. It does not by itself tell us how much of the earlier increase came from births. Statistics Canada’s 2021 census release Statistics Canada’s demographic profile
What period the figures describe
The Pew estimates combine data from censuses, surveys and other sources for 2010 and 2020. They count religious affiliation under broad categories, which can include people with quite different patterns of belief and worship. They also use estimates for the starting year that were revised for the 2025 report. The 21% figure describes change within that comparison. A claim about growth in a later decade would require data for a later period and comparable definitions. Pew Research Center’s 2010–2020 global comparison How Pew revised its 2010 baseline
Conclusion
Pew’s worldwide estimates identify Islam as the fastest-growing major religion from 2010 to 2020. North America had the fastest regional percentage increase in Muslim population, and its smaller starting population helps explain why it added fewer people than sub-Saharan Africa. The Canadian census illustrates how a national picture can add detail about migration and births. To interpret any claim about rapid growth, check the years, the geographic area and the population used as the denominator.
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