Commas and Coordinating Conjunctions (FANBOYS)

What are coordinating conjunctions, and when do you use a comma with them? Read on to tackle those pesky comma placements and raise your rating.

What is a coordinating conjunction?

A coordinating conjunction is a special word that joins two clauses of a sentence together. These special words are:

For
And
Nor
But
Or
Yet
So

which can be remembered through the acronym FANBOYS.

When do you use a comma?

There is a simple and effective test that you can use to determine if a comma is needed: Read each clause that is joined by the conjunction separately and see if it can stand on its own as a sentence. A clause that can stand on its own is also known as an independent clause. If both sides can stand on their own, a comma is required before the conjunction.

“I went to the store, and I bought some apples.”

Since “I went to the store” and “I bought some apples” are both independent clauses, this comma is required.

However, if one of the clauses cannot stand on its own as a complete sentence (aka a dependent clause), do not separate the clauses with a comma.

“I went to the store and bought some apples.”

Since “bought some apples” is a dependent clause, do not use a comma before the conjunction.

The trick with “nor”

Although the test works for any of the FANBOYS. “Nor” can be a little tricky. Just look for the subject in the second clause. If the subject is included in the second clause, use a comma. Otherwise, do not use a comma.

“I could not lift the boulder, nor could I budge it.”

The subject “I” is included in the second clause, so the comma is required.

“I could not lift the boulder nor budge it.”

No subject, no comma.

Imperative sentences with FANBOYS

Imperative sentences are sentences that command the reader to do something, such as “Call us now” or “Read ahead.” Imperative sentences are independent clauses, so when one is joined to another independent clause with a coordinating conjunction, a comma is required before the conjunction. Here are some various examples.

Imperative to imperative:
“Go to your room, but don’t slam the door.”

Imperative to an independent clause with a different subject:

“Pull your car forward, and the mechanic will service your car.”

Imperative to an independent clause with the same subject:

“Grab your keys, and you can drive to the store.”

Independent to imperative with subject change:

“The doctor will see you now, so grab your things.”

Independent to imperative with the same subject:

“You can go to the store, but don’t forget to grab cat food.”

Do not split a compound predicate with a comma, however.

“You can go to the store and buy some apples.”

This sentence does not use a comma because it lists two things that the reader can do: “go to the store” and “buy some apples.”

With these tips and some practice, you’ll be well on your way to mastering the FANBOYS comma.

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