When to Use a Colon: Rules
and Examples
By Ali
Hale
The colon
can be a tricky punctuation mark. You’ve probably grasped periods, question
marks, exclamation points, and commas – but the rules surrounding colons may
seem a bit trickier.
There are
two main ways to use colons:
- To introduce an item or a series of items.
- To replace a semi-colon between two independent clauses: the second clause should explain or expand on the first in some way.
As you
can see, I’ve used both types of colon above.
Colons
can trip writers up, though. Perhaps you’re not sure whether to use a capital
letter after a colon, or you’re unsure how to structure a list of items that
follows a colon.
We’re
going to go through some key rules that will hopefully clear things up.
Rule #1: Use a Colon to Introduce One or More
Items, When Punctuation is Required
Here are
some examples of colons being used correctly, preceding an item or multiple
items when the sentence requires punctuation at that point.
I needed
just one thing: courage.
(Not “I
needed just one thing courage.”)
Bring the
following equipment: a torch, warm clothing, and waterproof boots.
(Not
“Bring the following equipment a torch, warm clothing, and waterproof boots.”)
However,
you should not use a colon if the sentence does not require punctuation.
For
instance, the following sentences are correct without a colon:
I needed
courage.
(Not “I
needed: courage.”)
You
should bring a torch, warm clothing, and waterproof boots.
(Not “You
should bring: a torch, warm clothing, and waterproof boots.”)
Rule #2: Use a Colon Before Listing Items with
Bullet Points
It you’re
listing items line by line, you should use a colon to introduce the list – even
if that same colon wouldn’t be required for a list in sentence form. Here’s an
example:
You
should bring:
- A torch
- Warm clothing
- Waterproof boots
Rule #3: Be Consistent With Punctuation of Bullet
Points
When
using a colon to introduce a list in this way, capitalization and ending
punctuation aren’t always necessary.
If each
item on the list is a complete sentence, you should always capitalize the first
letter and finish with a period (or question mark or exclamation point, if
appropriate). In other cases, though, it’s up to you whether or not you want to
capitalize and use periods – just be consistent.
You
should bring:
- A torch.
- Warm clothing!
- Waterproof boots.
This
example is consistent because each item ends with a punctuation mark: either a
period or an exclamation point.
Rule #4: Carefully Consider Capitalizing a Complete
Sentence After a Colon
Some
editors believe that it’s always best to capitalize a complete sentence that
comes after a colon, like this:
He asked
for help: He got it.
Others
believe that you should generally avoid capitalizing in this way, instead
preferring:
He asked
for help: he got it.
Some
would say that you don’t need to capitalize if the clause after the colon bears
a close relationship to the clause before the colon, but would capitalize a
general or formal statement, such as:
Remember
what your mother taught you: If you can’t say anything nice, don’t say anything
at all.
In these
cases, it’s best to either consult the style guide for the publication you’re
writing for, or to create a consistent style guide for your own work.
There are
a couple of cases in which you should always capitalize the sentence after a
colon, though.
When it’s a Complete or Full Sentence Quotation
The chair
made an announcement: “This meeting will have to be postponed.”
In that
example, “This” has to be capitalized because it’s the start of a full sentence
quotation.
When the Information After the Colon Requires Two
(or More) Sentences
The rules
were inflexible: No running in the corridors. No shouting. Always walk on the
right.
In this
case, it makes sense to capitalize the first “No” because it’s the first of
three full sentences.
Rule #5: Use a Colon to Introduce an Extended
Quotation
Whether
you’re writing an essay, a non-fiction book, or a blog post, there’ll be times
when you want to quote someone else at some length (more than a sentence or
two). This means using a “block quotation” that goes in its own standalone
paragraph. This should normally be preceded by a colon, and should be indented
from the left margin – some style guides also indent from the right margin.
In 26 Feel-Good Words,
Michael wrote:
Some
writers neglect the power of emotion when communicating their ideas, valuing
logic more than others do, and assuming that everyone thinks like they do –
that careful reasoning is enough to convince readers and make points. But even
the ancient Greek philosopher Aristotle, who was no enemy of reason, taught
that stimulating emotion in your audience can be the key to persuading them.
Rule #6: Use a Colon After the Salutation in a
Business Letter (Depending on Where You Live)
In
American and Australian usage, the salutation (greeting) should be followed by
a colon in formal correspondence – this applies whether you’re using someone’s
surname or first name:
Dear Mr
Richardson:
Informal
or personal correspondence uses a comma in place of this colon.
In
British English, though, you should use a comma after the salutation – never a
colon – for formal business letters as well as for informal letters.
Colons
can take a bit of practice, so try using one (or more!) in the next piece that
you write. You’ve probably already used them to introduce lists, but how about
structuring a sentence that has two independent clauses joined by a colon? Drop
us a comment below to share your examples.
