Why do we need punctuation?
Punctuation marks are essential when you are writing. They show the reader where sentences start and finish and if they are used properly they make your writing easy to understand. This section gives practical guidance on how to use commas, semicolons, and other types of punctuation correctly, so that your writing will always be clear and effective. There are also sections which offer advice on using punctuation when writing direct speech, lists, or abbreviations.
You may find some aspects of punctuation harder to grasp than others (for example, when to use a semicolon or a colon). Clicking on each heading will take you to a page with more details and full information.
Types of punctuation
Periods are used:
- to mark the end of a sentence that is a complete statement:
All their meals arrived at the same time.
- to mark the end of a group of words that don’t form a conventional sentence, so as to emphasize a statement:
It's never acceptable to arrive late. Not under any circumstances.
Please return the form by Monday, Dec. 8 at the latest.
- in website and email addresses:
A comma marks a slight break between different parts of a sentence. There are four common occasions on which commas are necessary; follow the links for more information.
- Using commas in lists (e.g. The flag was red, white, and blue.)
- Using commas in direct speech (e.g. "That's not fair," she said.)
- Using commas to separate clauses (e.g. As we had already arrived, we were reluctant to wait.)
- Using commas to mark off parts of a sentence (Her best friend, Eliza, sang for a living.)
The semicolon is most commonly used to mark a break that is stronger than a comma but not as final as a period. It’s used between two main clauses that balance each other and are too closely linked to be made into separate sentences. For example:
The movie was a critical success; its lead actors were particularly praised.
There are three main uses of the colon:
- between two main clauses in cases where the second clause explains or follows from the first:
We have a motto: live life to the fullest.
- to introduce a list:
The cost of the room included the following: breakfast, dinner, and Wi-Fi.
- before a quotation, and sometimes before direct speech:
The headline read: "Local Woman Saves Geese."
There are two main cases where apostrophes are used:
Malcolm's cat was extremely friendly.
We took a day trip to the Gibsons' house.
I'm afraid the pie isn't suitable for vegetarians.
We didn't think about the consequences of our actions.
Hyphens are used to link words and parts of words. There are three main cases where you should use them:
My mother-in-law is visiting soon.
The novel is clearly intended to be a post-Marxist work.
He collects eighteenth- and nineteenth-century vases.
There are two main occasions on which an em dash can be used, usually in informal writing:
- to mark off information that is not essential to an understanding of the rest of the sentence
Many birds—do you like birds?—can be seen outside the window.
- to show other kinds of break in a sentence where a comma, semicolon, or colon would be traditionally used
Tommy can't wait for Christmas—he's very excited.
Parentheses are mainly used to separate off information that isn’t essential to the meaning of the rest of the sentence: He asked Sarah (his great-aunt) for a loan. Brackets (also called square brackets) are mainly used to enclose words added by someone other than the original writer or speaker, typically in order to clarify the situation: The witness said: "Gary [Thompson] was not usually late for work."
Quotation marks are mainly used in the following cases:
- to mark the beginning and end of direct speech:
"There wasn't," he said, "any need for you to say that."
- to mark off a word or phrase that’s being discussed, or that’s being directly quoted from somewhere else:
They called it the "land of milk and honey."
The "food" she put on our plates was inedible.
The main uses of the exclamation point (most commonly used in informal writing) are to end sentences that express:
Ow! That hurts!
direct speech that represents something shouted or spoken very loudly:
"Run as fast as you can!" he shouted.
something that amuses the writer:
They thought I was dressed as a smuggler!
An exclamation point can also be used in parentheses after a statement to show that the writer finds it funny or ironic:
He thought it would be amusing (!) to throw a plastic mouse at me.
A question mark is used to indicate the end of a question:
What time are you going to the fair?
A question mark can also be used in parentheses to show that the writer is unconvinced by a statement:
The bus timetable purports to be accurate (?).
Bullet points are used to draw attention to important information within a document so that a reader can identify the key issues and facts quickly.
You can read more rules and guidelines about punctuation on the Oxford Dictionaries blog. Here you will find further information and examples of correct and incorrect use of punctuation.