When and When Not to Put a Comma Before an And

CommaDo you know when to put a comma in front of an and in a sentence?

There are several grammatical rules that apply in that situation. Some rules dictate using the comma, other rules dictate not using a comma.

In The Series Comma, I wrote about the rules involved when using and in a series of items. This article is about another common problem I see when editing people’s writing.
Here are two examples:

  1. I carried my ladder out of the garage, and I climbed the ladder to get on the roof.
  2. I carried my ladder out of the garage and climbed the ladder to get on the roof.

See the difference?

The Comma with Independent Clauses

The first example has two independent clauses joined by the conjunction and. An independent clause is a group of words that contains a subject and a predicate and makes sense when it stands by itself. A conjunction is word such as and, or, and so that unites parts of a sentence.

The first example follows the rule of putting a comma in front of a conjunction when the conjunction is linking two independent clauses. You can tell both clauses are independent by removing the conjunction and seeing whether each sentence makes sense on its own.

“I carried the ladder out of the garage.”

“I climbed the ladder to get on the roof.”

Both of the sentences above make perfect sense by themselves, so the comma is correct. Using the comma tells the reader “You just read one complete sentence, and I’m using and to join another complete sentence to this one.”

The Comma with a Phrase

Although the second sentence in the example looks like the first, there’s a big difference. The words after the and aren’t a clause, they’re a phrase. A phrase is a group of words that does not contain a subject and a predicate.

Let’s remove the conjunction again and try each part of the second example as a separate sentence.

“I carried the ladder out of the garage.”

“Climbed the ladder to get on the roof.”

When the two parts are separated you can easily see the first sentence is an independent clause. It makes perfect sense by itself.

The second part, however, doesn’t make sense because it’s missing a subject. The sentence doesn’t say who climbed the ladder.

Not using the comma in the second example tells the readers, “You just read one sentence, and I’m telling you more about what the subject of that sentence did.”

Sometimes whether to use the comma in front of a conjunction is difficult to see. Just remember to break the sentence apart where the conjunction is and determine whether each part is a clause or a phrase. If both parts are clauses, use the comma in front of the conjunction. If one part is a phrase, don’t use the comma.

As Writing Jim, Jim Driggers provides copywriting and business process writing to owners of small and medium-sized businesses. His clients gain sales through marketing text that better resonates with their customers, and they save money when their employees follow guides rather than impulses. His clients give themselves the time to focus on what they do well when they leave their writing to Writing Jim.

For copywriting help with your print or online content or for help systematizing your business processes, contact Writing Jim at [email protected] or 925-231-5825. Visit www.writingjim.com for more information.

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