Title Case Capitalization Rules: Which Words to Capitalize

Title Case looks simple from a distance — capitalize the important-looking words — but it actually follows a specific, learnable rule set, and different style guides don't fully agree on the details. Knowing the real rule, rather than an intuitive guess at it, is especially useful for anyone writing headlines, article titles, or formal documents regularly.

The basic rule

Capitalize the first word and the last word of the title, always, regardless of what they are. Capitalize all "major" words in between — nouns, verbs, adjectives, adverbs, and pronouns. Lowercase the "minor" words — articles (a, an, the), coordinating conjunctions (and, but, or, nor), and short prepositions (in, on, at, of, to, for) — unless one of them happens to be the first or last word, in which case the always-capitalize-first-and-last rule overrides the minor-word rule.

Where style guides disagree

AP style lowercases prepositions of any length in the middle of a title, except when a preposition is functioning as part of a verb phrase (like "Look Up," where "Up" is treated as part of the verb rather than a simple preposition). Chicago style specifically lowercases only short prepositions (generally under five letters), meaning a longer preposition like "Without" or "Between" gets capitalized under Chicago rules even mid-title. Neither guide is more "correct" than the other — they're simply different conventions, which is exactly why picking one style guide and applying it consistently across a whole site or publication matters more than which specific guide gets chosen.

Common Title Case mistakes

The single most common mistake is capitalizing every word, including minor words that should stay lowercase mid-title — writing "The Guide To The Best Tools" instead of the correct "The Guide to the Best Tools." The second most common mistake runs the other direction: forgetting that the very last word of a title is always capitalized even if it's normally a minor word, so a title ending in "...Look It Up" needs "Up" capitalized specifically because it's the final word, not because of what part of speech it normally is.

A worked example

Take the sentence "a guide to writing headlines that get clicks." Applying the rule correctly: capitalize the first word ("A"), capitalize all major words ("Guide," "Writing," "Headlines," "Get," "Clicks"), lowercase the minor words in the middle ("to," "that"), and capitalize the last word regardless of type ("Clicks," which happens to already be major here). The correct result: "A Guide to Writing Headlines That Get Clicks" — note "That" stays capitalized here since it's functioning as a relative pronoun (a major word), not a minor conjunction, which is exactly the kind of nuance that trips up an intuitive guess. Running any title through this same process — capitalize first and last regardless of type, capitalize major words, lowercase minor words unless they anchor the title — resolves the great majority of real-world capitalization questions without needing to memorize a long list of exceptions.