There is no single agreed‑on number of logical fallacies, but most reference lists identify anywhere from a few dozen to several hundred distinct named fallacies.

Why the number varies

Different authors and logicians group, rename, or split fallacies in slightly different ways, so one source might count “ad hominem” as one fallacy while another breaks it into sub‑types (abusive, circumstantial, tu quoque, etc.).

  • Introductory logic or critical‑thinking guides often list around 15–25 common fallacies for teaching purposes.
  • More exhaustive catalogues (like the Wikipedia “List of fallacies” or specialized fallacy databases) list well over 100 , sometimes approaching 200 or more named fallacies.

Main categories of fallacies

Most systems sort fallacies into broad families:

Category| What it covers| Typical count range
---|---|---
Formal fallacies| Errors in deductive structure (e.g., invalid syllogisms) 57| Roughly 10–30 named forms
Informal fallacies| Errors in content, relevance, or evidence (e.g., ad hominem, straw man, slippery slope) 57| Often 50–150+ named types
Fallacies of relevance| Attacking the person, appealing to emotion, red herrings, etc. 59| Around 20–40 common ones
Fallacies of weak induction| Hasty generalization, false cause, false analogy, etc. 57| Roughly 15–30 core types

How to think about “how many”

Instead of a fixed number, it is more useful to think in terms of:

  • A core set of about 20–30 fallacies that show up very often in everyday debates and online forums.
  • A longer catalogue of 100+ named fallacies used in academic and reference works, many of which are niche or highly technical.

So if someone asks “how many logical fallacies are there,” a concise answer is:

There is no exact count, but standard lists usually include between about 20 and 200 named fallacies, depending on how finely they are categorized.

Information gathered from public forums or data available on the internet and portrayed here.