How to Use Commas

Commas are often seen as difficult, but the rules of how to use them are fairly simple. This is a grammar guide to using commas.

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Commas are one of those things that many writers struggle with, but when you break down the rules they’re actually not that bad.


You use a comma to separate the items in a list.

Lunch today consisted of a sandwich, an apple, and a piece of cake.

The second comma in this sentence is known as either the serial comma or the Oxford comma and isn’t as universally adopted as the standard comma. It does, however, help to alleviate confusion in some instances.

I went to the shops with Brian, my uncle and my father.

Without the final comma it is unclear how Brian is related to the narrator, or, for that matter, the nature of his relationship with the narrator’s mother.

I went to the shops with Brian, my uncle, and my father.

In fact, the narrator is talking about three people, which is clarified by the third comma.


If you are referencing the speech with a dialogue tag (such as he said) then a comma must precede or proceed the speech, depending on where the tag goes.

He said, “I’m happy.”

“I’m happy,” he said.

A comma inside of the speech marks is replaced by other grammar such as a question mark or an exclamation mark.

If you have two parts of speech in the same sentence that is broken up with a dialogue tag, the same rules apply.

“I’m happy,” he said, “because I like to dance.”

The dialogue tag both precedes and proceeds the speech so you need to have the commas in place for both of those.

Separating Clauses

A complex sentence has multiple clauses: a main clause plus a subordinate clause or clauses. You use commas to separate these.

Having spoken to Tim, I went back to work.

The main clause is the main part of a sentence, in this case going back to work, and the subordinate clause depends on the main clause for its meaning. Having spoken to Tim doesn’t make any sense as a standalone sentence, therefore is subordinate, whereas I went back to work works on its own.

There is also a restrictive relative clause that you don’t use commas for. This type of clause is vital for the meaning of the sentence.

People with dogs are wonderful.

The with dogs is the restrictive relative clause, so doesn’t require commas because of its importance.

A relative clause does require commas as it is not vital for the meaning.

Sally, who has a dog, is wonderful.

The relative clause of who has a dog isn’t vital to the overall meaning, therefore it requires commas.

Separate Parts of a Sentence

Much like clauses, you use commas to mark out an aside to the sentence.

Eugene’s wife, Tabitha, is a doctor.

The extra information isn’t needed so, much like relative clauses, it requires commas. Without them, it changes the meaning of the sentence.

Eugene’s wife Tabitha is a doctor.

The lack of separation implies that Eugene has more than one wife and that this sentence is referencing one of them, in this case Tabitha.


You need to use a comma when you insert a natural pause, often wrapped around consideration works.

It was, however, a nice cake.

Depending on your usage of these words, you do not always need to wrap them in commas. The easiest way it to say the sentence aloud—would you pause? If not, don’t use a comma.

However you take it, the medicine won’t work.

To add a comma after However would feel out of place, so here it is not necessary.


Commas aren’t the easiest thing to get your head around. However, with practice, it does become much more simple. By using a spellchecker or grammar-checking software, you will generally be alerted to where you have incorrectly used them—or missed them out—and will be able to pick up on the rules.

David Chitty was born and raised in Thanet in the 90s. He devotes most of his energies to writing fantasy fiction novels.

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