Chicago Style Title Case: The Complete Guide
Updated March 2026 · 9 min read
The Chicago Manual of Style (CMOS) has been the go-to reference for book publishers, academic presses, and editors since 1906. Its title case rules are arguably the most traditional of any major style guide - and for many writers, the most natural-feeling once you learn them.
What makes Chicago style stand out? It lowercases all prepositions, regardless of length. That single difference changes the look of a headline dramatically compared to AP style. This guide walks through every rule with clear examples so you can get Chicago-style capitalization right every time - or just use our free tool and let it handle the details.
In This Guide
What Is Chicago Style Title Case?
Chicago style title case is the headline capitalization system defined by the Chicago Manual of Style, now in its 17th edition. CMOS is the dominant style guide in book publishing, and it's widely used in magazines, academic journals outside of the sciences, and literary criticism. If you've ever picked up a novel and looked at the chapter titles, there's a good chance they follow Chicago rules.
The basic principle is the same as other title case styles: capitalize the "important" words and lowercase the "minor" ones. But Chicago defines those categories more strictly than most. Its treatment of prepositions - lowercase them all, no matter how long they are - is what gives Chicago-style headlines their distinctive, slightly more reserved look.
The Core Rules of Chicago Title Case
The Chicago Manual of Style (section 8.159 in the 17th edition) lays out these rules for headline-style capitalization:
- Capitalize the first word of the title or subtitle.
- Capitalize the last word of the title or subtitle.
- Capitalize all major words - nouns, pronouns, verbs, adjectives, adverbs, and some conjunctions.
- Lowercase articles - a, an, the.
- Lowercase prepositions - regardless of length (this is the big one).
- Lowercase coordinating conjunctions - and, but, or, nor, for, yet, so.
- Lowercase "to" in infinitives - "How to Write" keeps "to" lowercase.
- Lowercase "as" in any function - whether it's a conjunction, preposition, or adverb.
That preposition rule is the heart of Chicago style. While AP style capitalizes prepositions of four letters or more, Chicago keeps them all lowercase - "through," "between," "without," "against" - every single one stays down unless it starts or ends the title.
Words You Always Capitalize in Chicago Style
These word types are always capitalized when they appear in the middle of a title:
- Nouns - Book, University, History, Language, Author
- Pronouns - He, She, It, They, Who, That, Which
- Verbs (all of them, even short ones) - Is, Are, Was, Be, Do, Has, Goes
- Adjectives - New, First, Critical, Modern, American
- Adverbs - Not, Never, Very, Also, Often, Well
- Subordinating conjunctions - Because, Although, While, Since, If, Unless, After
Pay special attention to short verbs. Words like "is," "be," "am," "are," "do," and "go" are verbs - they get capitalized even though they're tiny. This trips people up constantly. "It Is What It Is" has every word capitalized because "it" is a pronoun and "is" is a verb.
Words You Keep Lowercase
Four categories of words stay lowercase in Chicago style (unless they begin or end the title):
- Articles - a, an, the
- Prepositions (all of them, any length) - at, by, for, in, of, on, to, from, with, into, over, through, between, without, against, under, before, after, around, during, toward, upon
- Coordinating conjunctions - and, but, or, nor, for, yet, so
- "To" in infinitives - to run, to write, to build
That preposition list is the critical difference. Look at "through," "between," "without," and "against" - these are long words that feel like they should be capitalized. In AP style, they would be. But Chicago keeps every preposition lowercase, no matter how many letters it has.
The Preposition Rule: What Makes Chicago Different
This is the single most important thing to understand about Chicago style. While AP style uses a simple four-letter cutoff (capitalize prepositions of four or more letters), Chicago takes a different approach entirely: prepositions are minor words, period. Length doesn't matter.
Here's how the same headline looks in Chicago vs. AP style:
Chicago Style
Walking through the Streets without a Map
AP Style
Walking Through the Streets Without a Map
"through" and "without" are lowercased in Chicago but capitalized in AP (5+ letters).
Chicago Style
The Relationship between Language and Thought
AP Style
The Relationship Between Language and Thought
"between" stays lowercase in Chicago despite being 7 letters long.
Some writers find Chicago's approach more elegant - it creates a cleaner visual distinction between content words and function words. Others find it strange to lowercase long words like "throughout" or "underneath." Either way, if your publisher or professor requires Chicago style, the rule is absolute.
| Preposition | Letters | Chicago | AP |
|---|---|---|---|
| in | 2 | lowercase | lowercase |
| with | 4 | lowercase | Capitalized |
| from | 4 | lowercase | Capitalized |
| through | 7 | lowercase | Capitalized |
| between | 7 | lowercase | Capitalized |
| throughout | 10 | lowercase | Capitalized |
Tricky Cases and Exceptions
The core rules cover most headlines cleanly, but a few situations require extra thought:
Hyphenated Compounds
Chicago has specific guidance here (section 8.161). In a hyphenated compound, capitalize the first element. Capitalize subsequent elements unless they are articles, prepositions, or coordinating conjunctions. So you'd write "Self-Sustaining Economy" but "Run-of-the-Mill Solution." If the compound starts the title, the first element is always capitalized. A prefix that can't stand on its own (like "anti-" or "pre-") keeps its second element lowercase only if that element is also not a major word: "Anti-intellectual" but "Anti-American."
Words Used as Other Parts of Speech
Some words can be prepositions in one sentence and adverbs or adjectives in another. "Up" is a preposition in "walking up the hill" but part of the verb in "Giving Up Hope." "Before" is a preposition in "the day before the test" but a conjunction in "Think Before You Speak." In Chicago style, you capitalize based on the word's function in the specific title - if it's acting as an adverb or part of a verb phrase, capitalize it.
The First Word After a Colon
Chicago capitalizes the first word after a colon in a title, whether or not it starts a complete sentence. This is different from AP style. So both "History: a New Interpretation" and "History: The Untold Story" would capitalize the word after the colon in Chicago style: "History: A New Interpretation" and "History: The Untold Story."
The Word "Not"
This one surprises people. "Not" is an adverb in Chicago style, so it's always capitalized. Write "What Is Not Said" rather than "What Is not Said." The same goes for "never," "very," "often," and other adverbs - they all get capitalized.
Species Names and Technical Terms
When a title includes a Latin species name or a technical term that has its own capitalization convention, follow that convention even inside a title. Homo sapiens stays lowercase for "sapiens" even in a headline. Brand names like "iPhone" keep their lowercase first letter.
Chicago Style Title Case Examples
Nothing teaches capitalization rules better than seeing them in action. Here are real-world examples with explanations:
Original
the art of writing through adversity and beyond
Chicago Style
The Art of Writing through Adversity and Beyond
"The" is capitalized (first word). "of" and "through" are prepositions - both lowercase. "and" is a coordinating conjunction - lowercase. "Beyond" is the last word, so it's capitalized.
Original
how to build a website without writing any code
Chicago Style
How to Build a Website without Writing Any Code
"to" is lowercase (infinitive marker). "a" is an article - lowercase. "without" is a preposition - lowercase even though it's 7 letters. "Any" is an adjective - capitalized.
Original
a comprehensive guide for students who are not sure where to begin
Chicago Style
A Comprehensive Guide for Students Who Are Not Sure Where to Begin
"A" is capitalized (first word). "for" is a preposition - lowercase. "Who" is a pronoun, "Are" is a verb, "Not" is an adverb - all capitalized. "to" in the infinitive "to begin" stays lowercase.
Original
what comes after the revolution: a look at political change
Chicago Style
What Comes after the Revolution: A Look at Political Change
"after" is a preposition - lowercase. "the" is an article - lowercase. "A" after the colon is capitalized (Chicago always capitalizes after colons in titles). "at" is a preposition - lowercase.
Original
between the lines: reading for what is not there
Chicago Style
Between the Lines: Reading for What Is Not There
"Between" is capitalized because it's the first word - but note that "between" in the middle of a title would be lowercase. "for" is a preposition - lowercase. "Is" is a verb and "Not" is an adverb - both capitalized.
Chicago Style vs. Other Capitalization Styles
Understanding where Chicago agrees and disagrees with other styles helps prevent the kind of mix-and-match errors that happen when writers switch between projects that use different guides.
| Feature | Chicago | AP | APA | MLA |
|---|---|---|---|---|
| Prepositions | All lowercase | 4+ capitalized | 4+ capitalized | Short lowercase |
| "with" capitalized? | No | Yes | Yes | Yes |
| "through" capitalized? | No | Yes | Yes | Yes |
| After colon | Always capitalize | Only full sentences | Always capitalize | Always capitalize |
| Short verbs ("is") | Capitalized | Capitalized | Capitalized | Capitalized |
| Primary use | Book publishing | Journalism | Social sciences | Humanities |
The practical takeaway: if you're used to AP style and switch to Chicago, the main adjustment is training yourself to lowercase those longer prepositions. "Lessons from the Past" (AP) becomes "Lessons from the Past" (same in both for short prepositions), but "Walking Through the Park" (AP) becomes "Walking through the Park" (Chicago). Our headline capitalizer supports both styles side by side so you can see the differences instantly.
Common Chicago Title Case Mistakes
These are the errors editors catch most frequently in manuscripts that are supposed to follow Chicago style:
Capitalizing long prepositions
The most common mistake by far. Writers capitalize "Through," "Between," "Without," or "Against" because they feel substantial. In Chicago style, these are always lowercase in the middle of a title. The length doesn't matter - only the function.
Lowercasing "not" and other adverbs
"Not" is an adverb, not a conjunction or preposition. It should always be capitalized: "What Is Not Said" is correct. The same goes for "never," "also," "very," and "so" when used as an adverb (though "so" as a conjunction is lowercase).
Mixing up prepositions and adverbs
Words like "up," "out," "off," and "down" can be prepositions or part of phrasal verbs. "Running up the Hill" lowercases "up" (preposition), but "Giving Up Hope" capitalizes "Up" (part of the verb "give up"). Look at what the word is doing in the sentence.
Forgetting to capitalize after a colon
Chicago always capitalizes the first word after a colon in a title, whether or not what follows is a complete sentence. This is different from AP style and catches writers who work across multiple style guides.
Lowercasing subordinating conjunctions
Words like "because," "although," "if," "when," and "while" are subordinating conjunctions - and Chicago capitalizes them. Only coordinating conjunctions (and, but, or, nor, for, yet, so) stay lowercase.
Try Chicago Style Capitalization
Not sure if that preposition should be lowercase? Paste your headline into our free tool and see it formatted in Chicago style instantly.
Capitalize My HeadlineQuick Reference
Bookmark this summary for the next time you need to format a Chicago-style headline:
- Always capitalize: First word, last word, nouns, pronouns, verbs (including "is," "be," "do"), adjectives, adverbs (including "not"), subordinating conjunctions.
- Always lowercase: Articles (a, an, the), all prepositions regardless of length, coordinating conjunctions (and, but, or, nor, for, yet, so), "to" before infinitive verbs, "as" in any function.
- After a colon: Always capitalize the first word.
- Hyphenated words: Capitalize both parts if both are major words; lowercase articles, prepositions, and conjunctions that follow a hyphen.
- Key difference from AP: Chicago lowercases ALL prepositions (through, between, without, against). AP capitalizes prepositions of 4+ letters.
Chicago title case might take a little practice if you're coming from AP style, but the rule is actually simpler once you know it: prepositions are always lowercase. No counting letters, no exceptions based on length. And whenever you're unsure, our headline capitalizer supports Chicago style along with AP, APA, and MLA - just select Chicago and type.