When to Use a Comma Before “And” | Useful Rules and Examples

Last updated on October 30, 2024 by Grammargeek

When to use a comma before “and” is a common question. Commas can be tricky, but they become easy once you know the rules. In this reference, you’ll learn about different situations where you might need to use a comma before “and.”

We’ll cover scenarios in the middle of a sentence and in lists. Whether it’s about joining items or separating clauses, understanding when to use that comma can make your writing clearer. Commas are a simple tool to improve your sentences.

When to Use a Comma Before AND In the Middle of a Sentence

When to Use a Comma Before AND
When to Use a Comma Before AND – Created by 7ESL

One of the most common ways to use the word and is in the middle of a sentence. You’re talking about one thing, and you add on something else. Do you need a comma?

It depends, but it’s really pretty easy to figure out with just one question: if you mentally delete “and,” does it leave you with two sentences, one on each side of the word? If the answer is yes, then you need a comma before and. It’s that simple!

Let’s look at some examples.

  1. I went to the store, and I brought my friend with me.
  2. I went to the store and brought my friend.

Because the second sentence has no subject after “and,” it doesn’t have two complete sentences and doesn’t need a comma before and. Adding a comma to the second sentence would be incorrect.

  1. My friend pets the cat, and my sister washes the dog.
  2. My friend pets the cat and washes the dog.

In this example, again, the second sentence contains only one subject. Since what comes after “and” is not an independent clause (a fancy name for “complete sentence” in this context), we should not use a comma before and.

Let’s look at one more set of examples.

  1. He wrote a sentence and punctuated it correctly.
  2. He wrote a sentence, and he punctuated it correctly.

Again, whether or not there’s a subject for the second part of the sentence tells us whether or not we need a comma. In the second sentence, we need a comma before and because we could make two complete sentences if we removed the word in question.

Simple enough, right? One quick note before we move on: this rule applies to all coordinating conjunctions. Coordinating conjunctions are the little words that join things together. You can remember them with the acronym FANBOYS: for, and, nor, but, or, yet, so. For all of these, we use the same rule we just learned for when to use a comma before and.

When to Use a Comma Before AND In a List

The other most common place to use the word “and” is to use it when listing people, places, things, etc. This one is a little trickier, but again, it’s easy once you get the hang of it.

If you’re only listing two items, you do not need a comma.

  • Jill and Jane went to the store to buy cookies and milk.

With just two items per list in that sentence (“Jill and Jane,” “cookies and milk”), no comma is necessary.

When a list has three or more items, we might want to add a comma before and. The tricky part is that the comma is optional but should be used consistently; if you use this comma at any point in your document (paper, letter, article, assignment, etc.), you should use it in every list in that document.

  • I bought cookies, milk, and ice cream.
  • I bought cookies, milk and ice cream.

While we need the comma between “cookies” and “milk” for both sentences, the comma before “and,” also known as the Oxford comma, is optional. Some prefer to avoid it; there are enough commas in the average piece of writing, anyway. Others say it helps avoid misunderstanding.

Let’s look at an example where it’s clearer to use a comma before and.

  • At the park, I saw the cats, Jimmy, and Justin.
  • At the park, I saw the cats, Jimmy and Justin.

In this example, it’s not clear whether Jimmy and Justin are actually the cats unless we use a comma before and.

Summing up: In the middle of a sentence, we use a comma before and if the and separates two independent clauses. In a list of three or more things, the comma before and is optional, as long as we’re consistent with whether or not we use it. It’s that easy!

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