How many books are in the Bible?
Clearly stated in Scripture
It depends on the tradition. Protestant Bibles have 66 books (39 Old Testament, 27 New Testament). Catholic Bibles have 73, and Eastern Orthodox canons have more.
The 27-book New Testament is shared across virtually all Christian traditions. The difference is in the Old Testament.
Protestant Bibles count 39 Old Testament books, for 66 total. Roman Catholic Bibles include seven additional deuterocanonical books (such as Tobit and Wisdom), reaching 73. Eastern Orthodox and other ancient churches include still more. So the honest answer names the tradition rather than a single universal number.
The count differs by tradition; all agree on the 27 New Testament books.