When to Use a Colon in a Sentence with Examples

1/9/2021

What is a colon in writing? Find out when to use a colon in a sentence with examples, when to use a colon or semicolon, and how to use a colon in a list.

When to use a colon in a sentence is between two clauses where the second clause (dependent) clarifies, highlights, reveals or adds emphasis to the first clause (independent); to introduce a list after a complete sentence; to introduce an indented block quotation; before speech/dialogue; and more.

If you’re not sure how to use the colon (:) in writing in order to be grammatically correct, which is not to be confused with a semicolon, read on to find out when to use a colon in a sentence with examples.

1. Between two clauses where the second clarifies, highlights, reveals or adds emphasis

Use a colon in a sentence if you have two clauses where the second clause (dependent) clarifies, highlights, reveals or adds emphasis to the first clause (independent). The first clause needs makes sense on its own, but the second clause doesn’t need to be stand-alone.

When to use a colon in a sentence with examples:

He began telling me about the Richter Scale: a system to assess the magnitude of earthquakes via their seismic waves (clarifies).
I asked for the urgent priority service to cross-check their medical records at the doctor’s surgery: they matched (reveals).
John Smith’s writing can be summed up in one word: amazing (highlights).
Just before I turned sixteen, we moved to a new area far away from everything we knew and loved: everything that felt right (adds emphasis).

Related Reading:

When to use a colon or semicolon?

The colon is often confused with the semicolon in similar sentence constructions. But a semicolon is used when both sentences/clauses are independent and make sense on their own (contains a subject and verb and expresses a complete thought).

Also, there is no need to capitalise the first word if you are providing just one sentence after a colon, use capitals and the appropriate punctuation as you would normally if there are two or more sentences.

2. To introduce a list after a complete sentence

Use a colon to introduce a list after a complete sentence when there isn’t an introductory term: for example, as follows, such as, namely these:

The following examples show how to use a colon in a list:

I provide professional editorial and writing services: proofreading, copy-editing, manuscript assessment and ebook formatting.
The cruise includes many excursions where you can stop off and explore for the day: Genoa, Florence, Naples, Dubrovnik and Venice.
There are many star constellations we can see in the night-time sky: the Big Dipper, the Little Dipper, Gemini, Hercules and Orion.

The same applies when introducing bullet lists.

There are mandatory sections you are required to complete:

Name
Address
Previous experience
Current employment
Specific skills relevant to this role

It isn’t always necessary to capitalise the first word and use full stops/periods when providing single words and phrases with bullet points. But it is usual if you are writing complete sentences. Whichever style you follow, remember to be consistent.

3. To introduce an indented block quotation

Use a colon to introduce quotations that are usually longer than three lines:

Love's Labour's Lost is one of William Shakespeare's earliest comedies. Here is an extract from Act IV: Scene 3 spoken by the character Lord Dumaine:

Love, whose month is ever May,
Spied a blossom passing fair,
Playing in the wanton air:
Through the velvet leaves the wind,
All unseen can passage find;
That the lover, sick to death,
Wish'd himself the heaven's breath.

Quotation marks are not used because the indentation indicates it is quoted material. Also, leave a blank line above and below the quoted text, and you should use single spacing. Check the relevant style guide, if you are using one, if you need to indent from the left margin only or both.

4. Before speech / dialogue

Use a colon before speech / dialogue (when the prior sentence is complete):

Every time I mentioned my dreams to be a sports star to Mum, her reply would always be the same: “Make sure you get good grades at school and you’ll be able to earn a living doing something you’re good at!”

5. More examples of colons used in writing

Some style guides (e.g. Chicago Manual of Style) recommend using a colon when writing the time:

12:25 p.m. / 4:05 a.m.

Between the chapter and verse of a Biblical reference:

John 9:12 (John, chapter 9, verse 12)

Use a colon to separate the main title in books and articles from a subtitle:

The Power of Now: A Guide to Spiritual Enlightenment by Eckhart Tolle

It is sometimes required to use a colon following a greeting (salutation) in formal business communications whether you are using the person’s first name, their full name or title (a colon or a comma can be used for personal documentation):

Dear Stephen:
Dear Stephen Brown:
Dear Sir:

Conclusion

In conclusion, the following applies when using a colon in a sentence:

In a sentence between two clauses where the first needs to be independent (makes sense on its own) and the second clarifies, highlights, reveals or adds emphasis (doesn’t need to be stand-alone).
To introduce a list after a complete sentence when there isn’t an introductory term: for example, as follows, such as, namely these.
To introduce an indented block quotation (usually longer than three lines).
A colon can also be used before speech (when the first sentence is complete).
Other uses of the colon include when writing the time, between Biblical references, separating the main title in books and articles from a subtitle, and it can be used in salutations in business communications.