In this article we’ll examine the similarities and differences between Title Case capitalization rules in the 8 major style guides, and explain what rules we chose for TitleFormat Title Case Converter.
The 8 Style Guides
The 8 most common style guides governing Title Case capitalization rules are:
- AMA (American Medical Association)
- AP (Associated Press)
- APA (American Psychological Association)
- Bluebook
- Chicago Manual of Style (CMOS)
- MLA (Modern Language Association)
- New York Times
- Wikipedia
As implied by the names, some of these guides have their roots in academia, and some in journalism. As a result, some are more prescriptive but complex to implement, and others offer more flexibility but possibly lack consistency.
(Almost) Universally Accepted Title Case Rules
All style guides agree on capitalizing the following parts of speech:
- First word
- Last word (with exception of APA, Bluebook, MLA who do not have a clear rule)
- Adjectives
- Nouns
- Pronouns
- Verbs
All style guides universally agree on lowercasing the following parts of speech:
- Articles
Yep, that’s it. Everything else has different interpretations or exceptions from guide to guide.
Capitalizing Adverbs
Adverbs are words that describe a verb, adjective, or another adverb. For example, The time seemed to finish too quickly.
Adverbs are generally capitalized, with the exception of as which is lowercased in Chicago and NY Times, and but which is lowercased in NY Times only.
Capitalizing Prepositions
Prepositions are words that govern, and usually precede, a noun or pronoun and expressing a relation to another word or element in the clause, as in she arrived after breakfast or the man on the moon.
All prepositions of two letters or less are lowercased by all guides with the exception of up which is capitalized in NY Times style guide.
So the prepositions at, by, in, of, on, to should all always be lowercase.
Three letter prepositions (but, for, off, out, via) should be lowercase according to all style guides except NY Times. NY Times capitalizes off and out. It also recommends capitalizing for in some cases.
Once we get to four letter prepositions the guides are split 50/50.
Bluebook, MLA, Chicago, and Wikipedia lowercase from, into, unto, and with, but AMA, APA, AP, and NY Times prefer to capitalize.
Once we get to five letters or more, only Chicago and MLA choose to lowercase words such as about, after, or behind. All other style guides capitalize prepositions of 5 letters or more.
Capitalizing Coordinating Conjunctions
A coordinating conjunction is a word that joins two elements of equal importance. There are 7 coordinating conjunctions; for, and, nor, but, or, yet, so. You can remember these using the acronym FANBOYS.
All style guides lowercase the coordinating conjunctions and, but, for, or. Chicago and NY Times capitalize yet and so whereas the others leave them lowercase. NY Times is alone in capitalizing nor.
Capitalizing Subordinating Conjunctions
Subordinating conjunctions are words that introduce a subordinate clause, for example although or because.
All style guides capitalize subordinating conjunctions with the exception of as which is lowercased by APA, AP, Chicago, and NY Times, and if which is lowercased by APA, AP, and NY Times.
“To” in Infinitives
The word to when part of an infinitive is generally lowercased, with the exception of AP style which recommends capitalizing.
Which Title Case Rules Should You Use?
If you are writing for a client or an organization you should check to see if they have a preferred style guide.
If you are writing a headline for your own blog or an article on Medium.com or Substack you are free to choose whichever title formatting style you prefer.
Selecting which style guide to use can be confusing in itself. And the complexities of some of the rules can lead to perceived lack of consistency from a reader point of view. For example, when following Chicago, the word like would be capitalized if it is an adjective but lowercased if it is a preposition. Futhermore some guides don’t have explicitly stated policy on key rules such as last word capitalization.
After many years experience writing articles online, and many years of finding that many of the other title case converters online gave titles that just didn’t look right, we built TitleFormat.
TitleFormat uses a custom set of rules cherrypicked from other guides which we believe offers the simplest, most consistent approach.
TitleFormat applies the following rules:
- Capitalize the first word
- Capitalize the last word
- Capitalize any words of 4 letters or more
- Do not capitalize articles (a, an, the…)
- Do not capitalize coordinating conjunctions (and, but, for…)
- Do not capitalize short prepositions (at, by, to, on…)
- Do not capitalize to in infinitives
- Capitalize the first part of a hyphenated word and subsequent parts, unless the word should be lowercased as per any of the above rules. eg “Case-by-Case”
Try it now on your headline.