CS Sealey

New Zealand-based sub-editor, writer and author

The importance of the comma

Ever wondered whether your writing is comma-happy or in need of some valuable punctuation? Well, here are a couple of tips on the usage of the all-important comma.

DISCLAIMER: Some of the following examples are purely my own style of writing. However, other examples, I think, are more of a necessary rule. Adopt all or some, but let this be your guide.


Commas are used to separate individual items in a list.

I needed two eggs, seven potatoes, a radish and four carrots from the grocer.

In the bag were copies of The Secret Garden, Peter Pan and The Cat Returns.

Note that a serial comma can be used in this situation thusly:

I needed two eggs, seven potatoes, a radish, and four carrots from the grocer.

In the bag were copies of The Secret Garden, Peter Pan, and The Cat Returns.

Both ways are correct, it simply depends on your own personal stylistic choice. Just make sure you are consistent in your writing—choose either to use it all the time or never, not sometimes.

2—Introductory Phrases

When a sentence begins with an introductory element, a comma is used to separate that element where the natural pause occurs, creating clarity and making the sentence easier to read.

On Thursday morning, I went down to the park.

Though the weather was absolutely dreadful, John still went for his evening walk.

From reading a variety of authors, I have found that a lot of them omit this particular type of comma. Though the human brain is capable of deciphering where the natural pause occurs, as a reader, it is much easier if the comma is included. However, don’t go overboard and put commas where they are not necessary.

It is with great sadness and sincere regret that I inform you of your wife’s death.

Note that there is no need to put a comma after regret, as the sentence flows on nicely without it, thanks to the presence of that.

3—Sentence Separation

Commas can also help divide a sentence into two individual clauses where separation is required for clarity.

He bent down to tie up his shoelace, then continued on.

It rained a lot in January, but February was much brighter.

The second example is a stylistic choice and can be omitted, providing that the conjunction but is an adequate separating device within the sentence. Most sentences including a but or because will not require a comma, especially in ones as short as those above. Other sentences, however, might require a comma to dispense with any unintended misunderstanding. For example:

I was certain the accident was all Jenny’s fault, because Clara was in the same classroom at the time and told me everything.

Without the comma, the sentence may be misinterpreted to meaning that the accident was Jenny’s fault because Clara was in the same classroom at the time, hinting that it might actually be Clara’s fault instead.


Technically referred to as parenthetical elements, an aside is a section of a sentence which, when removed, does not affect the overall meaning of the sentence.

When I arrived at the soccer pitch, after dodging some swooping magpies, my team was already training vigorously.

My cat Souk, who is absolutely mental, woke me up at four this morning for some attention.

Other asides can include:

Peter came first, George came second but, of course, I came last.

Other instances of a parenthetical element is during the writing of a date or a place. For example:

We are now arriving in Hamburg, Germany.

On the 20th of September, 1987, I was born.

Note that the comma after September is sometimes omitted, but I prefer to put them in. The comma after 1987, however, adheres to the above point on introductory sections.

5—Addressing in Speech

In direct speech, it is important to separate the name being addressed from the rest of the sentence. If not, some terrible misunderstandings could occur.

‘Eat, grandma!’ John said.

‘Eat grandma!’ John said.

Notice the difference in meaning? In the first instance, John is telling his grandma to eat. In the second sentence, the lack of comma transforms John’s speech entirely, making him appear to command someone to eat his grandma! One little comma just saved grandma’s life! Unfortunately, in this digital age, too many writers neglect to notice the difference, so eager are they to write down everything swimming around inside their minds. I’m surprised there are any grandmas left at all!

Other examples of this kind of mix-up are:

‘It’s red, Sally,’ George explained.

‘It’s red Sally,’ George explained.

The first sentence has George explaining to Sally that something is red. The second sentence has George explaining that Sally is red herself.

‘Can’t you see, Jordan?’ Gloria asked.

‘Can’t you see Jordan?’ Gloria asked.

In the first sentence, Gloria is asking Jordan whether or not he can see or understand something. In the second sentence, Gloria is asking someone whether or not they can see Jordan.

As these three examples have shown, commas are very important in these circumstances. Their absence could confuse a reader quite seriously!


When a character or object is described by more than one adjective, it may be necessary to separate these traits with commas. For example:

The pale, screaming child.

The wiry, shrivelled tree.

If you can replace the comma with an and while not affecting the meaning of the sentence, like the two examples above, a comma is necessary. However, other descriptions do not need a comma, for instance:

The red front door.

The little old woman.

It sounds awkward to say ‘the red and front door’ and ‘the little and old woman, therefore these sorts of descriptions do not require commas.

7—Dialogue and Quotations

Throughout school, university and my career thus far, I have been subjected to some of the worst written quotations imaginable. When writing direct speech, a comma is used correctly like so:

Josh stood up and said, ‘I’m ready. Let’s go!’

Bella blushed and admitted, ‘I don’t really know where we’re supposed to go.’

Here, a comma comes before the space and quotation mark, separating the prose from the dialogue.

Harry agreed quickly, saying, ‘Yes! I vote we have pizza!’

Note that there is a comma before and after saying. This is due to the fact that I wanted to clearly show that the adverb quickly belonged to agreed, not saying. It also adheres to the rule about introductory elements as explained earlier.

‘I’m so bored,’ moaned Pansy.

‘So am I,’ agreed Draco. ‘Let’s go annoy some First Years.’

Here, notice that the comma at the end of the quotation comes before the final quotation mark. One of the most common mistakes I come across is that a writer will put the quotation mark before the comma—this is incorrect.

‘It seems strange,’ David mused, ‘that we didn’t think of that before.’

In this instance, note how the commas are used to indicate that the two elements of speech are one continuous sentence, not two. If there were two sentences, it would look like this:

‘That’s just not fair,’ Alison complained. ‘I was here first!’

‘I was told to call this number if I was in trouble,’ Peter whispered urgently. ‘I think there’s someone after me.’

Note that fair and trouble are followed by commas, not full stops. When a piece of speech is labelled with the speaker’s name, use a comma in the ways demonstrated above. If you wish to have a series of fast back-and-forth exchanges between characters and don’t wish to label every element of dialogue, it may look like this:

‘I thought you said you’d be here at nine o’clock,’ Charles grumbled.

‘The traffic was terrible. I got here as fast as I could,’ James explained.

‘Then you should’ve called to say you were running late or something.’

‘My phone’s dead!’

‘Sure, whatever.’

‘Look,’ James said exasperatedly, ‘are you going to stand here all night, whinging and moaning, or can we go in and get a drink now?’

When using quotations in an essay or another type of formal writing, however, the quote should be written like so:

According to Jane Austen, sitting in the shade on a fine day ‘is the most perfect refreshment’, though I would personally prefer to stay indoors.

Here, the comma comes after the quote ‘is the most perfect refreshment’. This is due to the fact that, as explained in sentence separation earlier, sections of a sentence should be separated by a comma for the purposes of clarity. This is not a piece of direct speech, this is a quotation. Do not make the mistake of putting the comma before the final quotation mark, as in direct speech. They are different beasts, so treat them accordingly.

8—Contrasting Expressions

In instances where one thing is set in contrast to another, a comma should be used for clarity.

The thing that hurt me the most was her parting speech, not the slap she gave me.

The train is going to leave on Tuesday, not Wednesday.

9— Numbers

Sometimes, using a comma to separate groups of three figures in a number is necessary. I have found that this is another stylistic choice, as some writers will use a space instead, as you often see in phone numbers.



Now, there are other occasions where a comma might be needed and I gather you may still have questions. If none of the categories above shed any light on your particular query, go with your gut or contact me and I’ll do my best to enlighten you.

Good luck, writers, and treat your commas well.


ADDITION: 4th June

It has come to my attention that many writers misjudge what an aside actually is and create unnecessary asides in their sentences, such as:

‘My best friend, Caitlin, asked me to see a movie with her this weekend.’

The movie, Sin City, is one of my favourites.

In the above examples, the commas that surround Caitlin and Sin City are unnecessary. In fact, the addition of the commas in the first example suggests that the speaker is talking to Caitlin herself, which is not the case. Here is how those sentences should have been written:

My best friend Caitlin asked me to see a movie with her this weekend.

The movie Sin City is one of my favourites.

This is an example of an appositive, a group of words that provide additional information to the noun preceding it. This group of words, together with the noun, create a single descriptive unit that does not need to be separated by commas. Other examples include:

The Prime Minister David Cameron met with the Queen.

My aunt Susan is a good cook.

My crazy cat Suki did a backflip.

So when do you need to use a comma while providing additional information about the noun? When the information itself is unnecessary but merely extra information, creating an aside, then you are fully entitled to use commas. For example:

The Prime Minister David Cameron, a Conservative, met with the Queen.

CS SealeyArchiveContact