Do You Capitalize Words After a Colon? Rules for Every Style
Learn when to capitalize the word after a colon in titles and sentences, with APA, Chicago, MLA, and AP examples.
A colon creates one of the most common capitalization questions in English writing. Sometimes the word after a colon should begin with a capital letter. Sometimes it should stay lowercase. The answer depends on whether you are writing a title, a subtitle, or an ordinary sentence, and it can also depend on the style guide.
The easiest place to start is with titles. When a colon introduces a subtitle, major title styles capitalize the first word after the colon.
Colons in Titles
Consider:
writing better headlines: a practical guide
In title case:
Writing Better Headlines: A Practical Guide
“A” is capitalized because it begins the subtitle. It does not matter that “a” is normally a lowercase article in the middle of a title.
This position based rule is widely shared across APA, Chicago, MLA, and other title styles.
Why the First Word of a Subtitle Is Capitalized
A subtitle functions as a distinct title element. The colon signals a break between the main title and the secondary title.
Examples:
Memory and Learning: A Practical Introduction
Digital Publishing: The Editor's Guide
Writing Clearly: How Good Editors Improve Meaning
The first word after the colon receives an initial capital even when it is ordinarily a minor word.
APA and Colons in Titles
APA title case capitalizes the first word after a colon when it begins a subtitle.
Example:
Understanding Anxiety: A Guide for Students
APA sentence case also commonly capitalizes the first word of a subtitle in reference titles:
Understanding anxiety: A guide for students
Notice the difference. The first word after the colon is capitalized in both examples, but the rest of the subtitle follows the selected case.
Title case:
A Guide for Students
Sentence case:
A guide for students
This is an important distinction for APA references.
Chicago and Colons
Chicago title case also capitalizes the first word after a colon when it begins a subtitle.
Example:
Editing for Readers: A Modern Approach
The title and subtitle then follow Chicago capitalization rules.
In ordinary prose, Chicago capitalization after a colon depends more on what follows and how the sentence is structured. A colon does not automatically force a capital letter in every sentence.
MLA and Colons
MLA title style capitalizes the first word of a subtitle.
Example:
The Language of Film: An Introduction to Visual Storytelling
“An” is capitalized because it begins the subtitle.
MLA also distinguishes title capitalization from ordinary sentence punctuation. Writers should not assume that every colon in prose should behave like a colon separating a title and subtitle.
AP and Colons
AP writing can use a capital after a colon when what follows is a complete sentence, and title capitalization follows its own composition rules.
For a composition title with a subtitle:
A New Era: What Comes Next
the first word after the colon is capitalized.
Newsrooms may have additional house style for headlines, so the publication's own rules should be checked when necessary.
Colons in Ordinary Sentences
Now compare a normal sentence:
She brought three things: a notebook, a pen, and a charger.
The word after the colon is lowercase because it begins a list rather than a formal subtitle.
Another example:
There was one problem: the file was missing.
Some style systems would keep the following material lowercase when it is not being treated as a formally capitalized independent sentence. Others can capitalize a complete sentence after a colon under defined conditions.
This is why the title rule is easier than the prose rule.
Is a Complete Sentence After a Colon Capitalized?
The answer varies by style.
A sentence such as:
The conclusion was clear: The experiment needed to be repeated.
may be acceptable under a style that capitalizes a complete sentence following a colon.
Another style or editorial house rule may prefer:
The conclusion was clear: the experiment needed to be repeated.
If you are writing formal academic or professional prose, check the required manual rather than using a universal colon rule.
Colon vs Semicolon
A semicolon does not normally create the same capitalization effect.
Example:
The draft was complete; the editor still found several errors.
“The” stays lowercase because the semicolon joins related independent clauses.
A colon can introduce an explanation, list, quotation, or subtitle, so its capitalization behavior is more varied.
Colon vs Emphasis
Sometimes a colon introduces a single emphasized word:
There was one goal: clarity.
“clarity” does not need a capital simply because it follows the colon.
The function of the text matters.
Colons in Book and Article Titles
Titles often use a colon to divide a broad topic from a more descriptive subtitle.
Examples:
The Science of Memory: How We Learn and Forget
Editing Online: A Guide for Digital Writers
Research Methods: An Introduction for Students
Capitalizing the first subtitle word helps readers recognize the second title unit.
Multiple Colons
A title can contain more than one colon, although it can become difficult to read.
Example:
Writing for Research: A Guide to Evidence: Methods and Examples
This structure is legal punctuation, but the title may be clearer if rewritten.
If each colon genuinely introduces a new subtitle like unit, capitalization should follow the style's treatment of the new title element. In practice, good editing may be a better solution than stacking colons.
Colons and Quoted Material
A colon can introduce a quotation:
The editor gave one instruction: “Keep the opening short.”
The quotation begins with a capital because it is a complete quoted sentence, not because every colon demands capitalization.
If the quotation is a fragment, capitalization can differ.
How a Title Case Converter Should Handle Colons
When Title Case is active, the converter should recognize that a colon can introduce a subtitle and capitalize the first eligible word after it.
Input:
editing for clarity: the guide writers need
Output:
Editing for Clarity: The Guide Writers Need
When sentence case is active, the converter should treat the subtitle beginning separately:
Editing for clarity: The guide writers need
The exact result can depend on the intended style.
Common Mistakes
Lowercasing an article that starts a subtitle
Wrong:
Writing Better: a Guide for Editors
Better:
Writing Better: A Guide for Editors
Capitalizing every colon in ordinary prose
Wrong assumption:
Every word after every colon must be uppercase.
The actual rule depends on what the colon introduces.
Confusing subtitle capitalization with sentence capitalization
Titles have their own position based rules. Ordinary prose does not always behave the same way.
Forgetting proper nouns
Even when the style calls for lowercase after a colon, a proper noun keeps its capital.
Related Resources
Frequently Asked Questions
Do you always capitalize after a colon in a title?
When the colon introduces a subtitle, major title styles capitalize the first word of that subtitle.
Do you always capitalize after a colon in a sentence?
No. The answer depends on what follows and the style guide. Lists and sentence fragments often begin lowercase, while complete sentences can receive different treatment by style.
Is “a” capitalized after a colon in a title?
Yes when it starts a subtitle, as in Writing Well: A Practical Guide.
Does sentence case capitalize the first word of a subtitle?
In systems such as APA references, the first word of a subtitle is capitalized even though the rest of the subtitle remains sentence case.