When to Use a Comma Before “And”

Comma rules may seem arbitrary, but the proper use of commas can prevent misunderstandings. Sometimes English teachers describe commas as short pauses in the middle of a sentence. In contrast, periods indicate a full stop. Unfortunately, that explanation doesn’t describe all the nuanced situations that call for this multifaceted punctuation mark. Today, we’ll lay out the rules for using commas with the word “and,” and, luckily, those rules are simple. There are only two main circumstances when you’ll need to remember to use commas with “and”. 

First, you’ll (almost) always need a comma when you use the word “and” as a coordinating conjunction and place it between two independent clauses. Next, depending on the style guide you use, you may need to place a serial comma, also called an Oxford comma, before the word “and” when it’s used in a list. Other than that, try to follow the normal rules for using commas. If you can’t quite remember the rules, we’ve included a refresher at the end of this article. 

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Coordinating Conjunctions

When you want to join two independent clauses, you can either use a coordinating conjunction or a semicolon. You may find it helpful to memorize FANBOYS, the mnemonic device to help you recall the coordinating conjunctions. 

F – For

A – And

N – Nor

B – But

O – Or

Y – Yet

S – So

Imagine you have two independent clauses:

He studied.

They went to the grocery store to buy ice cream. 

You know that the clauses above are independent, not dependent, because they each stand alone as a complete sentence. If you want to join them together in a compound sentence, you could write the first independent clause, use a comma followed by a coordinating conjunction, then include the second independent clause. 

He studied, and they went to the grocery store to buy ice cream.

Now, imagine the above example without the second subject. “Went to the store to buy ice cream” would be a dependent clause because it doesn’t stand alone. If you remove “they” from the second clause, you would not need a comma before the word “and” and the rest of the sentence. 

He studied and went to the grocery store to buy ice cream. 

Although the two italicized sentences above look very similar, only one of them features two independent clauses joined by a coordinating conjunction. Therefore, only the first sentence requires a comma before the word “and”. 

Some stylebooks add an exception to this rule. When you combine two short independent clauses, you may choose to omit the comma. 

I walked.

+

She ran.

I walked, and she ran.  

In the example above, you may choose to forego the comma.

Serial Commas

When writing, authors must make some stylistic choices. For example, comma usage can sometimes be a matter of opinion rather than proper use. Some grammar guides recommend a serial comma, and others don’t. As a writer, you will have to decide whether to include a final comma before “and” and “or” in a list of three or more items. 

Let’s look at a simple list:

I need books, papers, pencils, and crayons. 

The comma before the word “and” in the sentence above is known as a serial comma. It’s also called an Oxford comma and a Harvard comma. That comma could be removed without changing the meaning of the sentence. 

I need books, papers, pencils and crayons.

Some style guides suggest using the extra punctuation mark, while others contend that the sentence works better without the last comma. A writer should make a decision about whether to use serial commas before the last item in a list, and then he or she should stick to that decision within a single composition. To avoid misreading, serial commas can be particularly useful in long, complicated lists. 

She wanted to play the harp, ski down the mountain, and entertain her guests. 

The comma before “and” in the sentence above is considered optional; however, if you’ve already introduced the use of a serial comma in the same piece of writing, you must continue to use it. Writers should remain consistent within the same work.

Other Grammar Rules

Now that we’ve covered the two main scenarios where you may need to introduce commas before the word “and,” we can move on to some of the general rules for comma usage. Some of these rules won’t be relevant to the word “and,” but other rules do apply.

Avoid Comma Splices

Never separate two independent clauses with just a comma. As mentioned above, you can only separate two independent clauses with a comma and a coordinating conjunction or with a semicolon. 

He studied; they went to the grocery store to buy ice cream.

He studied, and they went to the grocery store to buy ice cream.

Set Off an Introductory Phrase With a Comma

If a sentence begins with a prepositional phrase of more than four words, you should follow the phrase with a comma. The same rule holds true when a sentence begins with an introductory word or phrase or a transition. As it happens, this rule does not impact the word “and,” since you wouldn’t follow a prepositional phrase, introductory phrase, introductory adverb, or transition with a conjunction. 

Interestingly, he arrived 30 seconds after I did. 

Set Off an Appositive With a Pair of Commas

An appositive follows a noun and renames it. You may use the word “or” in this context, but you are unlikely to use the word “and” this way. 

Mi casa, or my house, has three rooms. 

Set Off an Inessential Clause With a Pair of Commas

Sometimes a sentence includes a parenthetical element or nonrestrictive clause. If you can remove the information without changing the meaning of the sentence, the clause or phrase should be separated from the main clause with commas. Typically, the word “and” will not introduce a nonessential, or nonrestrictive, clause. When it does introduce a parenthetical element, the aside should probably be marked off with em dashes or parentheses for added clarity. 

Restrictive clause: She wandered through the backyard that I designed before getting into the car.

Nonrestrictive clause: She wandered through the backyard, which was lovely, before getting into the car.

Parenthetical element: She wandered through the backyard (and it was a beautiful backyard) before getting into the car.

In the sentence above, the parenthetical element “and it was a beautiful backyard” must be sandwiched between commas, parentheses, or em dashes. Em dashes or parentheses make the sentence easier to read. A parenthetical element beginning with the word “and” is not a common construction. 

Commas in Dialogue

Writers often use commas to punctuate in and around dialogue that appears in quotation marks. The word “and” does not typically begin attribution for dialogue. When the word “and” is used within a quotation, it is unlikely to appear in a part of the sentence that requires special punctuation. 

“Are you hungry?”

“I’m a little bit hungry, and George is starving,” he answered. 

Use Commas With Coordinate Adjectives

Two adjectives of equal rank that describe a noun are called coordinate adjectives. Coordinate adjectives require a comma; however, you wouldn’t encounter the word “and” used in this context. If you use the word “and” between two adjectives, you don’t need a comma. For three or more adjectives, you may use an optional serial comma.

Non-coordinate adjectives: She’s a clever kindergarten student. 

Coordinate adjectives: She’s a clever, charismatic student.

List of adjectives: 

She’s a clever and charismatic student. 

She’s a clever, charismatic, and responsible student.

Additional Resources

For more information about the proper use of a comma, check out this article: “When to Use a Comma: Tips and Tricks.” 

To learn how to use a comma with the coordinating conjunction “but,” read this article: “Where Does the Comma Go—Before or After ‘But’?

Sources:

  1. https://www.businessinsider.com/a-guide-to-proper-comma-use-2013-9
  2. https://owl.purdue.edu/owl/general_writing/punctuation/commas/extended_rules_for_commas.html
  3. https://style.mla.org/serial-commas-and-semicolons/