When to use a comma in English
28 October, 2016 Education Erin O'Neill
Commas are one of the most frequently used punctuation marks in the English language- they’re also one of the most misused. Commas signify a pause between different parts of a sentence, making the meaning clearer and the writing easier to read. Despite being relatively easy to understand, it can be confusing deciding when to use them, with many people placing them throughout their text without knowing the proper rules.
Commas are incredibly versatile, and can indeed be used in many different situations. Getting used to when is and isn’t the right time to use a comma can be tricky, but there are some rules you can learn that will help you remember.
Commas can be used:
TO SEPARATE THE ELEMENTS IN A LIST OF THREE OR MORE ITEMS
Commas are needed in-between different items in a list.
E.g. We baked a vegetable pie using onions, carrots, broccoli, and potatoes.
There is some debate about whether the last comma (before and) is necessary. Often referred to as the ‘Oxford comma’, to be on the safe side it is advisable to use it; omission can sometimes lead to misunderstandings.
E.g. She thanked her parents, Sally Smith and God.
The above sentence is much less confusing when the Oxford comma is used:
E.g. She thanked her parents, Sally Smith, and God.
BEFORE SOME CONJUNCTIONS
A conjunction is a linking word. A comma is needed in a sentence before the conjunctions and, but, for, nor, yet, or, so to separate the two independent clauses.
E.g. She loved reading, so she spent every Sunday afternoon at the library.
You should always avoid putting a comma after the conjunction.
WHEN YOU ARE QUOTING DIRECT SPEECH
If the information about who is speaking comes before the piece of direct speech, you should use a comma before the first quotation mark.
E.g. Rachel replied, ‘See you tomorrow.’
If the information about who is speaking comes after the direct speech, you should use a comma at the end of the dialogue. The comma should go inside the quotation mark.
E.g. ‘The weather is terrible,’ she said.
TO SEPARATE CLAUSES
Some longer sentences are made up of more than one clause, a comma is used to separate these clauses. These type of sentences are referred to as complex, and contain a main clause and one or more subordinate clauses.
A main clause contains a subject and a verb, and expresses a complete thought that makes sense on its own.
E.g. After finishing work, I went shopping for some new clothes.
[Subordinate clause] [Main clause]
TO SEPARATE INTERCHANGEABLE ADJECTIVES
E.g. She was a capable, intelligent woman.
In this instance you can swap the adjectives around and say intelligent, capable woman.
E.g. We went to an expensive winter market.
We would not say winter expensive market, so no comma.
TO SEPARATE THE INTRODUCTION OF A SENTENCE
You can use a comma to separate the introductory part of a sentence from the main part.
E.g. The rain was atrocious, so our picnic had to be cancelled.
As you can see, there are a lot of rules concerning commas, and learning them can help you to improve your writing. You can always do your own research, and investigate the many more situations that you should use commas, and when it’s best to write a sentence without them. If you’re interested in improving your English grammar further, take a look at our blog post on ENGLISH GRAMMAR RULES.