Chicago Title Case: Tool Packer Profile and Examples

How the Chicago profile differs

The profile lowercases internal a, an, and the; for, and, nor, but, and or; as; and recognized prepositions of four letters or fewer. It explicitly capitalizes if, yet, and so. Recognized prepositions longer than four letters remain capitalized. The first and last words are capitalized, as are words following a colon, em dash, or line break.

That four-letter boundary reflects a notable change discussed by the Chicago Manual’s official Q&A for the eighteenth edition: prepositions longer than four letters are capitalized. Earlier editions lowercased prepositions regardless of length, so a workflow tied to an older edition may require a different result.

• with and from are lowercase internally.
• through, between, and without are capitalized internally.
• and and but are lowercase; If, Yet, and So are capitalized by this profile.

Compare with and without

The input “a guide to writing with and without fear” becomes “A Guide to Writing with and Without Fear.” To and with are within the profile’s lowercase threshold; and is one of the named coordinating conjunctions; without exceeds four letters and remains capitalized.

This same fixture exposes a difference from the AP and APA profiles, which capitalize With, and from MLA, which lowercases both with and without internally. Those results are useful for comparison because they come from one unchanged input rather than from handpicked titles with different grammar.

Grammar can override a word-list assumption

Chicago’s real guidance can depend on part of speech. A spelling such as up, over, like, or than may be a preposition in one title and another kind of word in another. Tool Packer does not parse the full syntactic structure; it applies a recognized preposition list consistently. That makes the result explainable, but not infallible.

Compounds are similarly bounded. The converter recognizes several hyphen characters and capitalizes major components while leaving internal articles, conjunctions, and prepositions lowercase, producing forms such as “State-of-the-Art.” Consult the current manual for a compound or grammatical edge case that affects publication.

• Use explanations to find which rule fired.
• Compare the word’s role with current CMOS guidance.
• Apply house style when it intentionally differs from Chicago.

Match the edition and publishing context

This profile is documented against the publicly described eighteenth-edition direction reviewed below. A publisher, editor, university, or project may still specify the seventeenth edition or a house adaptation. Record the governing edition when consistency matters across a long manuscript or team.

The Chicago Manual of Style is a registered trademark of the University of Chicago. Tool Packer is independent and neither endorsed nor certified by the University. Its profile covers repeatable capitalization choices only; it does not determine italics, quotation marks, citations, bibliography treatment, or design choices on covers and title pages.

• Confirm the required CMOS edition.
• Separate capitalization from citation and typography rules.
• Review high-stakes titles with a qualified editor.