The number of books in the Bible varies depending on the Christian tradition and its accepted biblical canon (the official list of sacred books). All major Christian traditions agree on the New Testament having 27 books (e.g., the four Gospels, Acts, the Epistles, and Revelation). The differences come from the Old Testament.
Here’s a clear breakdown of the most common versions:
Protestant Bible (used by most Protestant denominations, including Baptists, Methodists, Lutherans, Evangelicals, etc.): 66 books total
Old Testament: 39 books (matching the Jewish Tanakh/Hebrew Bible canon)
New Testament: 27 books
This is the version most commonly referred to in English-speaking contexts (e.g., KJV, NIV, ESV translations).
Roman Catholic Bible: 73 books total
Old Testament: 46 books (includes the 39 Protestant books plus 7 deuterocanonical books: Tobit, Judith, Wisdom, Sirach/Ecclesiasticus, Baruch, 1 Maccabees, 2 Maccabees, plus additions to Esther and Daniel)
New Testament: 27 books
These extra books are considered fully canonical by Catholics (called “Deuterocanonical” or “second canon”).
Eastern Orthodox Bible (used by Greek, Russian, and most other Orthodox churches): Typically 76–79 books (varies slightly by jurisdiction)
Old Testament: 49–52 books (includes the Catholic deuterocanonicals plus additional ones like 1 Esdras, 3 Maccabees, Prayer of Manasseh, and sometimes Psalm 151 or 4 Maccabees in an appendix)
New Testament: 27 books
Other variations:
Ethiopian Orthodox Bible: Up to 81 books (includes even more unique texts like Enoch and Jubilees in some lists).
Oriental Orthodox or other ancient traditions may have slight differences too.
The reason for these differences traces back to history: Early Christians used the Greek Septuagint (which included the deuterocanonical books), but during the Protestant Reformation in the 16th century, reformers like Martin Luther aligned the Old Testament more closely with the Hebrew canon (excluding those extra books, often calling them “Apocrypha”). Catholic and Orthodox traditions retained the broader Septuagint-based canon affirmed by early church councils.
If someone asks “How many books are in the Bible?” without specifying, they usually mean the Protestant count of 66, as that’s the most widespread in many parts of the world (especially the U.S. and English-speaking countries). But the full answer is: It depends on the tradition—66 (Protestant), 73 (Catholic), or 76+ (Orthodox).
Which tradition’s Bible are you most familiar with, or is there a specific one you’re curious about?