Catholic Church

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Lore & Background

According to the 2025 Pew Research Center study, the Catholic Church is the largest Christian denomination, with 1.3 billion baptized members. The study also notes that Christianity is the predominant religion in Europe, the Americas, Sub-Saharan Africa, and Oceania, and that the United States has the largest Christian population in the world, followed by Brazil, Mexico, Russia, and the Philippines. Additionally, the source lists several nations where Christianity in multiple forms is the state religion, including Costa Rica (Catholic Church), Liechtenstein (Catholic Church), Malta (Catholic Church), Monaco (Catholic Church), and Vatican City (Catholic Church). No further historical or doctrinal details about the Catholic Church are provided in the source.

Reader's Guide

The source provides limited information about the Catholic Church specifically. It states that the Catholic Church has 1.3 billion baptized members, making it the largest Christian denomination. The source also identifies several countries where Catholicism is the state religion: Costa Rica, Liechtenstein, Malta, Monaco, and Vatican City. For context, the source notes that Christianity as a whole had 2.3 billion adherents in 2020, representing 28.8% of the global population, and that 120 out of 201 countries and territories had Christian majorities in 2020. No further guidance on practices, beliefs, or governance is available from the source.

Did You Know?

• The Catholic Church has 1.3 billion baptized members, making it the largest Christian denomination according to a 2025 Pew Research Center study.
• Christianity as a whole comprised 2.3 billion people—28.8% of the world's population—in 2020.
• The United States has the largest Christian population in the world, followed by Brazil, Mexico, Russia, and the Philippines.
• Catholicism is the state religion of Costa Rica, Liechtenstein, Malta, Monaco, and Vatican City.
• In 2020, 120 out of 201 countries and territories had Christian majorities, four fewer than in 2010.

Global Scale and Demographic Weight

As of 2020, roughly 2.3 billion people worldwide identified as Christian, placing the faith at approximately 28.8 percent of an estimated eight-billion-person global population. A 2025 Pew Research Center study confirmed Christianity as the single largest religious tradition on Earth. A separate tally from World Population Review placed the figure slightly higher at 2.38 billion by 2021. Within that vast body of believers, the Catholic Church stands as the largest single denomination, counting 1.3 billion baptized members. It is important to note that these numbers are statistical estimates rather than precise censuses. They are compiled by aggregating denomination membership rolls and self-identified Christians along with their children, meaning the figures capture affiliation and identity rather than measuring the depth of personal belief or regular worship attendance. The data therefore reflect a broad sociological category of religious belonging rather than a theological or devotional count.

Denominational Architecture and Classification

Christianity is not a monolithic institution but a family of traditions, and the three largest branches are the Catholic Church, Protestantism, and the Eastern Orthodox Church. The Catholic Church holds the top position with its 1.3 billion baptized adherents. The question of which branch ranks second, however, is not settled by the data themselves but by how one draws the boundaries of Protestantism. If the thousands of Protestant denominations are treated as a single collective group, Protestantism claims the second-largest position. If, conversely, each Protestant body is counted as a separate denomination, then the Eastern Orthodox Church may edge ahead. This classification issue matters because it changes how scholars, policymakers, and interfaith dialogues frame the competitive landscape of world religions. The Catholic Church's numerical lead is unambiguous, but the rest of the Christian family's internal hierarchy remains sensitive to definitional choices.

Geographic Reach and State Recognition

Christianity holds a position of religious predominance across Europe, the Americas, Sub-Saharan Africa, and Oceania, while also maintaining substantial communities in Central Asia, the Middle East, and West Africa, where it typically ranks as the second-largest faith behind Islam. In 2020, one hundred twenty of the two hundred one countries and territories surveyed had a Christian majority, a figure four lower than the 2010 count. The United States holds the world's largest Christian population, followed by Brazil, Mexico, Russia, and the Philippines. Beyond sheer numbers, Christianity enjoys formal state-religion status in fourteen nations, including Costa Rica, Liechtenstein, Malta, Monaco, and Vatican City for the Catholic Church; England for the Church of England; Denmark and Iceland for their respective Lutheran bodies; and Armenia, Georgia, and Greece for their Orthodox traditions. The former Ethiopian Empire, which adopted Christianity in 340 A.D. under the Kingdom of Aksum, also held this status until its government was overthrown.

Shifting Majorities and Future Trajectory

The religious map is in motion. During the twenty-first century, Christianity lost its majority position in the United Kingdom, Australia, and France, where the religiously unaffiliated now constitute the largest group. Conversely, Madagascar and South Sudan each gained a Christian majority in the twentieth and twenty-first centuries respectively, and South Korea saw Christianity overtake Buddhism as the dominant faith. Looking ahead, a 2015 Pew Research Center projection estimated that Christianity would reach roughly three billion adherents by 2050 out of a projected global population of 9.3 billion. That figure would mark the first historical parity with the Muslim population, predicted at approximately 2.8 billion in the same year. A 2012 Pew survey concluded that, if current demographic trends persist, Christianity will retain its position as the world's largest religion through 2050, even as the gap between the two major faiths narrows for the first time.