FANBOYS commas are those that must be placed 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.
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. When joining clauses, these conjunctions will always need to be preceded by a FANBOYS comma; when joining words and phrases, 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
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 before coordinating conjunctions within compound subjects and predicates unless creating a list of three or more items:
- Yes: Alice and the Hatter drank tea and ate bread and butter, but the Dormouse slept and snored. (Both Alice and the Hatter did these things, but the Dormouse did those other things.)
- No: Alice and the Hatter drank tea, and ate bread and butter, but the Dormouse slept, and snored. (Both predicates—sets of verbs—are just two items joined by “and,” which does not require a comma, while the coordinating conjunction between the two clauses does.)
- 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 the 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
- Video (14:20): "Writing Skills: When to Use Commas with For, And, Nor, But, Or, Yet, So," JamesESL
- Handout (printable): "Commas vs. Semi-colons," Purdue OWL
- Exercises: "Commas with Coordinating Conjunctions," ProProfs
- Webpage: "Commas," University of North Carolina Chapel Hill
- Exercises: "Rearranging simple and compound sentences," Khan Academy
The following index makes searching for a specific topic easier and links to the appropriate place in the sequenced material. We think we have most of them, but please email us at firstname.lastname@example.org if we are missing something!