The Short Answer
Paul wrote thirteen books in the New Testament, assuming you count all the traditional attributions. That is not a complicated number to defend if you just look at the table of contents and read the bylines. Romans through Philemon, plus the Thessalonians, Corinthians, Galatians, Ephesians, Philippians, Colossians, Timothy, Titus, and Hebrews in some traditions. Thirteen is the standard answer. Fourteen if you count Hebrews, which nobody actually knows who wrote. I ran into this question myself when someone tried to use authorship counts as proof for a specific theological timeline. They wanted to argue that Paul could not have written certain letters because the chronological math did not line up. The problem was not the number of books. It was that they assumed all thirteen were written in sequence during one continuous ministry, which they were not. Paul was imprisoned, released, imprisoned again, and active in between. The gap between 1 Thessalonians and Philemon spans roughly a decade with large stretches of undocumented activity. I usually recommend pulling out a simple timeline from a reference Bible or an academic source like the Anchor Yale Bible Dictionary and checking dates against events rather than just counting letters.
Here is where beginners miss the real issue. Authorship attribution in Pauline studies is not a single category. Scholars divide the letters into three groups: the undisputed seven, the disputed six, and Hebrews, which is a separate problem entirely. The undisputed Paulines are Romans, 1 and 2 Corinthians, Galatians, Philippians, 1 Thessalonians, and Philemon. These show consistent style, vocabulary, and historical grounding that most scholars accept. The disputed group includes Ephesians, Colossians, 2 Thessalonians, 1 and 2 Timothy, and Titus. The language shifts, the church structure described looks more developed, and the Greek is measurably different. Some researchers argue Paul used a different scribe or editor for those. Others say he wrote them later in life with different co-senders and a adjusted rhetorical approach. Both positions exist inside peer-reviewed journals, so treating any single answer as definitive is naive. Hebrews is its own mess. It has no authorship claim inside the text. The early church debated it for centuries. Jerome and Augustine placed it under Paul in Latin tradition, which is why many Bibles still attribute it, but the Greek is distinctly different from the rest of the corpus and the theological argumentation follows a different pattern. Modern scholarship overwhelmingly treats it as anonymous. I usually tell people to count it separately rather than lump it into the Pauline total.
If you want a practical way to handle this, use a source like the New Oxford Annotated Bible or the HarperCollins Study Bible. They list manuscript evidence, date ranges, and scholarly disagreements in the headnotes. Most beginner commentaries just repeat tradition without flagging uncertainty, which is why the fourteen-book answer survives in casual conversation. There is also a limitation worth noting. The thirteen-count method collapses entirely if you apply it to canon debates. Catholics, Orthodox, and Protestants disagree on what counts as Pauline or even canonical in some cases. The Ethiopian Orthodox canon includes a Pauline Epistle to the Laodiceans that does not appear in any surviving Greek manuscript and is considered a later composition by most historians. If you are answering this for a church class, check which canon your instructor is using before you commit to a number. The actual writing process probably involved amanuenses, which changes how you should interpret stylistic variation. Romans explicitly mentions Tertius as the scribe who wrote it down. A letter dictated through a trained secretary will naturally absorb some of that secretary's phrasing and rhetorical habits. That is normal first-century practice, not a forgery signal. When you see vocabulary overlap between disputed and undisputed letters, do not assume plagiarism. Assume a shared scribal school or extended dictation practice.
Get the Full Details
I have found the most reliable quick reference for this is the section on Pauline authorship in the Cambridge Companion to St. Paul, edited by James D.G. Dunn. It walks through the criteria without pretending certainty exists where it does not. For a more accessible option, Bart Ehrman's book on the New Testament covers the disputed letters with actual manuscript evidence instead of devotional claims.
