Commas are for when you take a breath, right?
The idea that commas can be used, at whim, to decorate your text – like sprinkles on a cake – is sadly a myth (everybody gasps).
Whatever your primary school teacher may have told you in Year 4 (thank you Mrs Willington), comma placement isn’t decided by when you need to breathe; the comma is, in fact, an extremely useful and precise tool for making your meaning clear. Once you learn how to use it correctly, your life – and your writing – will never be the same again.
Below, I have explained my six favourite points about comma use. (Yes, there’s more than six. Crazy times.)
1. The dreaded comma splice
On this subject, I’m going to break the mould and start with the don’ts before the dos. The dreaded comma splice is too important to wait until the end of this post. Remember, it is simply not possible to join two separate clauses with a comma:
Megan loves crime dramas, she watches them every night.
Each of these clauses has a subject and verb. They are independent causes and cannot be joined by simply dropping a comma in between.
There are three easy ways to correct this:
1. Start a new sentence: Megan loves crime dramas. She watches them every night.
2. Use a semi colon (if the two clauses are closely related): Megan loves crime dramas; she watches them every night.
3. Use a conjunction (also sometimes called a connective): Megan loves crime dramas, so she watches them every night.
Having said all of this, there are exceptions to the rule. If the sentence is very short and the writing is informal, you can get away with using a comma splice for effect (although it’s still not grammatically correct).
I loved Broadchurch, they didn’t.
But, don’t make a habit of it!
2. The serial comma
Nope, not a homicidal punctuation mark, although that does sound like an interesting idea for a horror novel. Most people are comfortable with this use of the comma to separate items in a list.
Yesterday I bought apples, oranges and eggs from the supermarket.
What most people don’t know about is the Oxford comma. Yes, I know that you’re now imagining a comma wearing a monocle and listening to classical music. The Oxford comma is not the little-known extra sidekick to Inspector Morse, but a comma before the final ‘and’ item, used to make complicated lists clear. For example, look at the two sentences below:
I had a party and invited my friends, Poirot and Sherlock Holmes.
I had a party and invited my friends, Poirot, and Sherlock Holmes.
In the first example, without the Oxford comma, a reader may well believe that Poirot and Sherlock Holmes are the friends I am inviting to my party (exciting, but probably something for my therapist to discuss). In the second, it’s clear that I invited my friends, and in addition invited Poirot and Sherlock Holmes (who sadly aren’t my friends as they are fictional characters, and therefore still fodder for my therapy sessions). In this type of sentence, the Oxford comma is necessary to make your meaning clear.
The Oxford comma is not typically used in journalistic writing unless its omission would cause confusion. However, it is used widely in fiction writing, and it’s one of my personal faves as far as comma uses go.
3. The comma between adjectives
Have you ever looked at a comma between adjectives and known that it looks weird without quite understanding why?
There are two types of adjectives: gradable (sometimes called qualitative) and classifying. Gradable adjectives are ones that you can use with very, for example happy or stupid. Classifying adjectives can’t be used with very (or in the comparative or superlative form), for example annual or American.
No comma is needed to separate adjectives of different types: A small American detective.
A comma is needed to separate two or more qualitative adjectives: A small, grumpy detective.
No comma is needed to separate two or more classifying adjectives if they relate to different groups: A medieval American detective.
4. The comma after introductory words or phrases
We use introductory phrases a lot, so this is a great rule to learn. Any extra information that we use before the main clause needs to be marked off by a comma. This is true for time phrases, adverbs and adverbial phrases.
After I finish chatting to Miss Marple, I will go and do some actual work.
Unfortunately, I have no intention of stopping.
New Hart’s Rules states that a comma isn’t essential if the introductory phrase is short and specifies time or location.
In 2020 I became obsessed with comma use.
Also, if the meaning is unambiguous, then you can risk omitting the comma, but don’t blame me if the grammar police come a-knocking!
Obviously I didn’t mean it.
5. The comma for connectives and subordinate clauses
When you’re joining clauses with a coordinating conjunction like 'but', 'for', 'yet', or 'and', it’s standard to put a comma before the conjunction.
I read the latest Shetland book, and I loved it even more than the previous one.
I want to to read other genres, but I’m currently addicted to crime.
If the clauses are very short and closely connected, the comma can be left out.
Poirot solved the crime and Hastings watched.
The comma can also be omitted if the subject in each clause is the same and can be left out of the second clause.
Poirot solved the crime but didn't have time to celebrate.
6. The comma for dependent clauses
When you start a sentence with a dependent clause, it should usually be followed by a comma. If you’re now slapping your forehead and crying, “What’s a dependent clause?!” then don’t panic. A dependent clause is generally introduced by conjunctions such as 'if', 'when' or 'because'.
If I continue to imagine that fictional characters are my friends, they may well lock me up.
But note, when the dependent clause comes after the main clause and is essential to meaning, you don’t use a comma.
They will lock me up if I continue to imagine fictional characters are my friends.
Ta da! There are my six favourite comma points all in one lovely blog post for you.
There are a lot more comma uses than I could cover in this one post, but if you’re really interested in the comma (and why wouldn’t you be?) you can read all about it in style guides such as The Chicago Manual of Style or New Hart’s Rules.
And, if you have no idea what a style guide is, check out my earlier post: Style Eternal: The Secret to Using Style Guides