When to use a colon

Key learning points

Colons are punctuation marks that look like this :

They are very useful grammatical tools which can help you to:

• introduce lists (like this one!)
• introduce quotations
• include extra information
• separate closely-related clauses

Colons are really useful punctuation marks which can be used in a number of ways: to introduce a list, extra information or quotations and also to separate clauses.

Did you notice the colon in that last sentence? That’s an example of how useful colons are.

The important thing to remember when using a colon is that it should only be used after an independent clause.

Find out more about different sentence types.

Colons can be used to introduce a list. It might help to think of the colon as being like the phrase ‘and these are’. Let’s look at an example:

I have three pets and these are a cat, a dog and a parrot.

We can replace ‘and these are’ with a colon to introduce the list:

I have three pets: a cat, a dog and a parrot.

Notice that the phrase before the colon is an independent clause. This is important. When you want to use a colon to introduce a list, you need to first write an independent clause, so that the colon can be used like the phrase ‘and these are’.

I have: a cat, a dog and a parrot.

This example is incorrect, as the phrase before the colon (‘I have’) is not an independent clause. If we replace the colon with ‘and these are’, we can see it doesn’t work.

Find out about when you would use semicolons in a list.

Colons can also be used to introduce extra information. The phrase that comes after a colon explains or expands upon what came before it. Here are a few examples:

• I love pizza: pepperoni is my favourite topping.
• We’re going to the library later: I need to get some new books.
• Colons are really useful: they can help to introduce extra information.

When using a colon to introduce information, it might help to think of the colon replacing the word ‘because’. Replace the colons in the examples above with the word ‘because’ and you will see that it still makes sense.

You can use a colon to introduce a quotation. This is really useful when you are writing about texts and you need to quote from the text.

For example, if you wanted to explain that the start of Shakespeare’s Romeo and Juliet gives away the end of the play, you could use a colon to introduce a quotation, like this:

At the start of Romeo and Juliet, Shakespeare reveals the ending: ‘a pair of star-crossed lovers take their life.’

This is correct because the colon comes after an independent clause and introduces a quotation.

At the start of Romeo and Juliet, Shakespeare writes: ‘a pair of star-crossed lovers take their life.’

This is incorrect because the phrase before the colon is not an independent clause. This sentence doesn’t need a colon.

You can use a colon to separate two independent clauses which are closely related. You can also use a full stop to separate independent clauses, but a colon is helpful to emphasise the connection between the two clauses. Here are some examples:

Exercise is good for your health. There is no arguing with this fact.

Here the full stop separates the two independent clauses completely. However, we might want to emphasise their connection a little more.

Exercise is good for your health: there is no arguing with this fact.

Using a colon to separate the clauses has a slightly different effect: it gives more of a sense that the clauses are connected.

In situations where you want to show a really close relationship between two independent clauses, a semicolon might work better than a colon. Find out more about how to use semicolons.

To ensure you are using colons correctly, here are some examples of common errors to avoid.

• Colons should only be used after independent clauses.

  • For my birthday, I got: a bike, new jeans and some books. - is incorrect
  • For my birthday I got lots of presents: a bike, jeans and books. - is correct

• Don’t use a colon after a subordinate clause. You should be able to replace a colon with a full stop, as you only use a colon after an independent clause.

• Colons should only be used to separate clauses which are closely related.

  • I like playing tennis: I am in year seven at school. - is incorrect
  • I like playing tennis: I have been playing tennis for three years. - is correct

• Don’t try to use a colon to separate clauses which are not closely related. A full stop will work much better for separating clauses which are not closely related.