“Should this word be capitalized in my title?” looks like a simple question until you realize the answer depends on which style guide you follow. AP, Chicago, and MLA each have their own title capitalization rules, and they disagree on the details — especially around short words, prepositions, and hyphenated terms. This guide lays out the rules for all three so you can capitalize any headline, article title, or heading correctly and consistently.
Title case vs sentence case
First, a quick distinction. There are two broad ways to capitalize a title:
- Title case capitalizes the important words: “The Lord of the Rings.”
- Sentence case capitalizes only the first word (and proper nouns): “The lord of the rings.”
This guide is about title case, which is what AP, Chicago, and MLA all use for titles and headlines. If you’re weighing which approach to use in the first place — for headings, buttons, or UI — see title case vs sentence case for when each one fits.
The core rule all three guides share
Despite their differences, AP, Chicago, and MLA agree on the foundation:
Always capitalize:
- The first and last word of the title, no matter what they are
- All nouns, pronouns, verbs, adjectives, and adverbs
- Subordinating conjunctions (because, although, if, while, that)
Always lowercase (when they fall in the middle):
- Articles: a, an, the
- Coordinating conjunctions: and, but, or, nor, for, so, yet
- Short prepositions: at, by, in, of, on, to, up (length rules vary — see below)
So in every style, “The Art of War” capitalizes The, Art, and War but lowercases of. The disagreements are all about the edge cases.
Where the guides differ
The main battleground is prepositions and how their length affects capitalization.
| Rule | AP Style | Chicago | MLA |
|---|---|---|---|
| Prepositions of 4+ letters | Capitalize (Over, With, From) | Lowercase all prepositions regardless of length | Lowercase all prepositions regardless of length |
| Short prepositions (of, to, in) | Lowercase | Lowercase | Lowercase |
| Coordinating conjunctions (and, but, or) | Lowercase | Lowercase | Lowercase |
| First/last word | Always capitalize | Always capitalize | Always capitalize |
| ”To” in an infinitive | Lowercase | Lowercase | Lowercase |
The headline difference: AP capitalizes prepositions that are four letters or longer. So AP writes “A Walk Through the Woods” (capitalizing Through), while Chicago and MLA write “A Walk through the Woods” (lowercasing it). If you’ve ever seen the same title capitalized two different ways, this rule is usually why.
The same title in three styles
AP: “How to Build a Cabin Without Spending a Fortune” Chicago: “How to Build a Cabin without Spending a Fortune” MLA: “How to Build a Cabin without Spending a Fortune”
The only difference is Without — capitalized in AP (five letters), lowercase in Chicago and MLA. Everything else matches.
Tricky cases worth memorizing
A few situations cause more errors than the basic word categories:
- Hyphenated words. Chicago capitalizes both parts of a hyphenated compound if both are significant: “State-of-the-Art Design” → “State-of-the-Art.” Generally capitalize the first element always, and the second if it’s a noun, adjective, verb, or proper noun.
- Phrasal verbs. The particle in a phrasal verb (the up in “Set Up”) is treated as part of the verb and capitalized — don’t mistake it for a preposition.
- “To” in infinitives. Always lowercase: “How to Win,” not “How To Win.” This is one of the most common mistakes.
- First word after a colon. All three styles capitalize the first word of a subtitle: “Deep Work: Rules for Focused Success.”
- Very short titles. In a two-word title where both words would normally be lowercase, the first/last-word rule wins, so both get capitalized anyway.
A step-by-step method
When you’re capitalizing a title by hand, work through it in this order:
- Capitalize the first and last words unconditionally.
- Capitalize every noun, pronoun, verb, adjective, and adverb in between.
- Lowercase articles (a, an, the) and coordinating conjunctions (and, but, or, nor, for, so, yet).
- Handle prepositions by your style: lowercase all of them in Chicago/MLA; in AP, lowercase those under four letters and capitalize those with four or more.
- Check the tricky cases: lowercase infinitive to, capitalize phrasal-verb particles, and apply your hyphen rule.
That’s a reliable process, but it’s also fiddly — and easy to get wrong when you’re capitalizing dozens of headings or doing it repeatedly. The case converter applies title-case rules instantly: paste any title, click Title Case, and it capitalizes the significant words and lowercases the small ones for you. It’s the fastest way to standardize a batch of headings without ticking through the rules by hand each time.
Why consistency matters
Inconsistent title capitalization is one of those small errors that quietly undermines polish. A blog where some headlines are in title case and others slip into sentence case looks careless, and mismatched capitalization across a site’s navigation or buttons reads as sloppy even when readers can’t say why. Pick one style guide for your project and apply it everywhere — including in your SEO elements, where a clean, correctly capitalized headline carries into the title tag and the clickable headline that readers actually see.
The bottom line
All three major style guides capitalize the first word, the last word, and every major word (nouns, verbs, adjectives, adverbs, pronouns), while lowercasing articles and coordinating conjunctions. The big difference is prepositions: AP capitalizes those four letters or longer; Chicago and MLA lowercase them all. Lowercase the infinitive to, capitalize phrasal-verb particles, and pick one style for the whole project. When you’d rather not apply the rules by hand, the case converter handles title case in one click.
Frequently Asked Questions
What words are not capitalized in a title?
In title case, you lowercase articles (a, an, the), coordinating conjunctions (and, but, or, nor, for, so, yet), and short prepositions (of, to, in, on, at) — unless they’re the first or last word of the title, which are always capitalized.
What is the difference between AP and Chicago title capitalization?
The main difference is prepositions. AP style capitalizes prepositions that are four letters or longer (Over, With, From), while Chicago lowercases all prepositions regardless of length. So AP writes “A Walk Through the Woods” and Chicago writes “A Walk through the Woods.”
Do you capitalize “to” in a title?
Lowercase to when it’s part of an infinitive verb, as in “How to Win.” Some style guides also lowercase to as a preposition. The common mistake is writing “How To Win” — the to should be lowercase.
Do you capitalize “is” in a title?
Yes. Is is a verb, and all three major style guides capitalize verbs in titles — including short ones like is, are, and be. Short length doesn’t make a word lowercase; its part of speech does.
How do you capitalize a hyphenated word in a title?
Capitalize the first part of the hyphenated word, and capitalize the second part if it’s a noun, adjective, verb, or proper noun. Chicago, for example, renders it “State-of-the-Art.” Minor second elements (like a lone preposition) stay lowercase.
How can I automatically convert a title to title case?
Paste your text into the case converter and choose Title Case. It capitalizes the significant words and lowercases articles, conjunctions, and short prepositions automatically — useful for standardizing a batch of headings quickly.