Title case is a capitalisation style used for titles (hence the name), in which “major” words are capitalised while “minor” words are not. You might think this would be easy but it turns out to be a lot more complicated than you’d think – especially once you take into account that various style manuals, like AP or MLA, actually have different rules that they apply to tell the difference.
The basic rule is to capitalise every word in a title except:
- articles (a, the, my, your…)
- coordinating conjunctions (and, or, but…)
- (short) prepositions
It’s the “prepositions” part that causes the trouble. The reason is that many English prepositions aren’t used only as prepositions, but also as adverbs or even adjectives. For example, in “the cat jumped on the table” on is a preposition, but in “keep on trying” it’s an adverb, and in “turn the TV on” it’s an adjective. So if those were all titles, they’d be capitalised The Cat Jumped on the Table, Keep On Trying and Turn the TV On respectively.
Now with that noted, there are still a number of differences in how different style manuals treat prepositions:
- The AMA, APA and AP only lowercase two- and three-letter prepositions; those of four letters or more are all capitalised
- Wikipedia and Bluebook lowercase prepositions up to and including four letters in length, but capitalise those five letters or longer
- CMOS and MLA lowercase all prepositions regardless of length
- The New York Times lowercases a selected list of two- and three-letter prepositions (like in, at, by), while capitalising others of the same length (including up, off and out), as well as all prepositions of four letters or more
Oh, and you know what? Lower-casing conjunctions isn’t a safe rule either, sorry. Style manuals also vary in how they treat those:
- AP and APA lowercase all seven coordinating conjunctions (and, for, but, or, nor, yet, so) and both subordinating ones (as and if)
- AMA, MLA, Bluebook, and Wikipedia lowercase all seven coordinating ones (and, for, but, or, nor, yet, so) but capitalise the two subordinating ones (as and if)
- CMOS lowercases most of the coordinating conjunctions but not yet or so, which it capitalises. As far as the subordinating conjunctions go, they lowercase as, but capitalise if.
- The New York Times capitalises nor, yet and so and lowercase the other coordinating conjunctions (and, but, or, for). They also lowercase both subordinating conjunctions (as and if).
Another rule that many style guides have is that they always capitalise the last word of a title. AMA, APA and Bluebook do not have this rule though.
So what does all of this mean for some random person not writing for traditional publication?!? Well for a start, it means it’s OK to correct Hugo if it lowercased some letter in your title that made it look weird to you, if you want, because chances are it did something like misinterpret an adverb as the literally identical preposition form of the word (rookie mistake). Overall I think just try your best. If someone ever tries to quibble with your capitalisation choices, just say you’re following some style guide with which they must be unfamiliar 🙃 Honestly, learning about all the ways in which different outlets disagree has made me relax because there’s no single “correct” choice for all these kinds of borderline words, in the end.
If you are writing for traditional publication, and you can’t rely on some tool like Zotero to implement the correct style for your chosen style format or something? Use a different tool, like Title Case Converter , from which I got most of this info on all the different variations in the first place.