Method and sources
How we know this
FaithShift visualises published research, not our own guesswork. Everything on the globe traces back to a citable source.
Sources
- Pew Research Center — Global Religious Landscape, 2020 baseline (published 2025): adherents, shares and median age for every faith on this site.
- Pew Research Center — Religious Change Around the World (2025): religious switching rates and join-to-leave ratios across 36 countries.
- National censuses: India (2011), England & Wales (2021), Australia (2021), Brazil (2022), Canada (2021).
- United Nations World Population Prospects: population totals used to convert shares into people.
Countries mapped
36
Faith categories
9
Baseline year
2020
Questions people ask
- What counts as a religious conversion?
- We use religious switching: an adult who no longer identifies with the religion they were raised in. It captures formal conversion, quiet drift and disaffiliation alike, and it is the only conversion measure collected consistently across dozens of countries.
- Which religion is growing fastest?
- Islam, but almost entirely through demography rather than conversion — Muslims have the youngest median age of any major faith. The group growing fastest through conversion is the religiously unaffiliated.
- Which religion loses the most people to conversion?
- Christianity. Across the countries Pew surveyed, far more adults leave Christianity than join it, with the losses concentrated in high-income countries and offset by growth in sub-Saharan Africa.
- Why is India shown as almost unchanged?
- Pew's survey of nearly 30,000 Indian adults found 98% still identify with the religion they were raised in — one of the lowest switching rates recorded anywhere.
- Are these numbers exact?
- No. They are best-available estimates rounded to whole percentage points, blending census returns, large national surveys and demographic projection. Treat them as the shape of the change, not a headcount.