Yes, the word all must be capitalized in titles, even though it only has three letters. That’s because the word class, not the word length, is the primary criterion for determining whether a word should be capitalized in title case. Only three word classes are not capitalized: articles, conjunctions, and prepositions. All is none of those; it’s an adjective, adverb, pronoun, or noun. Hence, all must always be capitalized in headings and titles, as in these examples:
Against All Odds
Jack of All Trades
Rockin’ All over the World
[NB: In AMA, AP, APA, and New York Times style, over needs to be capitalized.]
If there are more words whose capitalization you’re not sure about, check out the other articles in this blog, or simply use the Title Case Converter to have your titles converted automatically.
Photo: Derick McKinney