Commas, FANBOYS - Graduate Writing Center

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Commas, FANBOYS


FANBOYS commas are those that must come before a coordinating conjunction (indicated by the acronym FANBOYS) when it joins two independent clauses—statements that could otherwise stand on their own as complete sentences:

  • Alice drank tea, but the Dormouse slept.
  • The March Hare dipped his watch into his tea, for he was altogether mad.
  • The Walrus and the Carpenter invited the oysters on a walk, and the oysters came along, so the Walrus and the Carpenter ate them.

Note that joining independent clauses in this way requires both the comma and the conjunction; joining independent clauses with a comma alone is an error called a comma splice.

Also keep in mind that, while all coordinating conjunctions can join independent clauses, some of them—and, nor, but, or, yet—can also join words and phrases. In this situation, they only need a comma if they form a list:

  • Yes: the Walrus and the Carpenter
  • No: the Walrus, and the Carpenter
  • Yes: the Walrus, the Carpenter, or the oysters

Compound Subjects and Predicates

These properties can also be combined. Remember that a clause is a subject–verb unit that can comprise multiple subjects and verbs (known as compound subjects and predicates). Take care not to insert commas within compound subjects and predicates unless creating a list of three or more items:

  • No: Alice and the Hatter drank tea, and ate bread and butter, but the Dormouse slept, and snored.
     
    • While the coordinating conjunction between the two clauses ("but") requires a comma, both predicates—sets of verbs—are just two items joined by “and,” which does not require a comma.
       
  • Yes: Alice and the Hatter drank tea and ate bread and butter, but the Dormouse slept and snored.
     
  • Yes: Alice, the Hatter, and the March Hare drank tea, ate bread and butter, and were altogether mad, but the Dormouse simply closed his eyes, rolled over, and went back to sleep.
     
    • The compound subject is a list, which requires commas; both predicates are also lists of verbs and so require commas. The coordinating conjunction, "but," must also be preceded by a comma.

For more information on such constructions, see our page on serial commas.

Breaking down a sentence into grammatical units and making sure the commas are placed correctly can be tricky, but remember that, the more care you take with your writing, the less work readers will have to do to understand it. Incorrect comma usage can trip readers up, while correct comma usage will be nearly invisible, in the best possible sense.

More Information about FANBOYS Commas

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Writing Topics A–Z


This index makes findings topics easy and links to the most relevant page for each item. Please email us at writingcenter@nps.edu if we're missing something!

A-Z content menu

A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q R  S  T  U  V  W  X  Y  Z

A

abbreviations

abstracts

academic writing

acronyms

active voice

adjectives, compound

advisor, selecting and working with

AI

apostrophes

appointment with GWC coaches, how to schedule

argument

article usage

artificial intelligence

assignments, understanding them

audience

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B

body paragraphs

booking an appointment with a GWC coach

brackets, square

brainstorming

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C

capitalization

citations

charts

ChatGPT

citation software

citation styles

clauses

clarity

clustering

coaching, about

coaching, how to schedule

colons

comma splices

commas, FANBOYS

commas, introductory

commas, list

commas, nonessential / nonrestrictive information

commas, Oxford

commas, serial

common knowledge

commonly confused words

compare-and-contrast papers

compound adjectives / modifiers

concision

conclusions

conference presentations

conjunctive adverbs

coordinating conjunctions

copyright and fair use

critical thinking

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D

dangling modifiers

dashes

dependent clauses

dependent marker words

display equations

distance learning

double submission of coursework

drafting

Dudley Knox Library

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E

editing your own work

editing: outside editors

em dash

en dash

equations

exclamation points

executive summary

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F

FANBOYS

FAQs

figures

first person, use of in academic writing

footnotes

fragments

free-writing

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G

generative artificial intelligence (AI)

gerunds

grammar

graphics

graphs

group writing

GWC appointment, how to schedule

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H

homophones

Honor Code, NPS

human subjects research

hyphens

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I

ibid.

incomplete sentences

independent clauses

Institutional Review Board

interviews, conducting

introductions

IRB

iThenticate

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J

Joining the Academic Conversation

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L

LaTeX

library liaisons

lists, syntax of

literature reviews

logic and analysis

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M

M dash

making a GWC appointment

mathematics

memos

methodology

modifiers, compound

modifiers, misplaced

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N

N dash

nominalizations

note-taking

noun clusters

numbers

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O

organization

outlining

Oxford comma

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P

paragraph development

parallelism

paraphrasing

parentheses

parts of speech

passive voice

periods

persuasion

phrases vs. clauses

plagiarism, how to avoid

plagiarism-detection software

plain language

polishing

prepositional phrases

prepositions

pronouns, clarity with

pronouns, grammar of

proofreading

publishing

punctuation

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Q

questionnaires, administering

questions

quotation marks

quoting

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R

Reading with Intent I

Reading with Intent II

redundancies

reference software

reflection papers

research

research guides, discipline-specific

research questions

restrictive vs. nonrestrictive information

reusing papers

reverse outlining

revision

roadmaps

run-on sentences

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S

scheduling a GWC appointment

self-citing

semicolons

sentence fragments

serial comma

signal phrases

significance

so what?

source blending

sources, engaging with / critiquing

sources, evaluating the reliability of

sources, citing

spelling

standard essay structure

STEM / technical writing

Strategic Reading I

Strategic Reading II

style

subject–verb agreement

subjects, grammatical

subordinating conjunctions

summarizing

surveys, administering

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T

tables

teams, writing in

technical writing

tense

that vs. which

thesis advisor, selecting and working with

thesis process overview

Thesis Processing Office (TPO)

thesis proposals: common elements

thesis statements

thesis writing

this, that, these, those

tone, professional

topic sentences

transitions

types of papers

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U

United States or U.S.?

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V

verbs and verb tense

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W

which vs. that

why write?

writer’s block

writing in groups / teams

writing process

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Z

Zotero

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