My Tool Studio
Text Tools·4 min read

Title Case Style Guides Compared: AP vs Chicago

Ask three editors to capitalize 'a guide to working from home' and you'll get at least two different answers, each one defensible. Title case isn't a single standard, it's a family of feuding ones. Here you'll find title case style guides compared properly: how AP and Chicago disagree, what happens to small words in titles, and how an automatic converter decides. One real headline gets worked through both rulebooks so you can see exactly where they split.

Open the toolAll insights

Why title case still trips up professional writers

It looks easier than it is.

Capitalize the big words, lowercase the little ones. That's the folk version of title case, and it survives until the first hard case arrives. Is 'is' a little word? It's two letters, but it's a verb, and every major guide capitalizes verbs. What about 'with'? Four letters, preposition, and the answer genuinely depends on which style guide your publication follows.

The cost of getting it wrong is credibility rather than clarity. Readers still understand a mis-capitalized headline, but editors, clients, and detail-oriented customers notice, and inconsistency across a site reads as carelessness. Teams that publish daily need the rules applied the same way by every writer, which is precisely what humans are bad at and automation is good at.

Title case style guides compared: AP against Chicago

The four-letter fault line.

AP style, the newsroom standard, has a mechanical core: capitalize every word of four or more letters, plus all verbs, nouns, pronouns, adjectives, and adverbs regardless of length. So AP writes 'Working From Home' because from has four letters, and capitalizes Is and Be because they're verbs.

Chicago, the book publishing standard, ignores length and rules by part of speech: prepositions stay lowercase no matter how long, so 'Working from Home' keeps from down, and even between and through stay lowercase in Chicago headlines. The ap vs chicago capitalization split explains most title disagreements you'll ever witness. Neither is wrong. Pick the guide that matches your world, journalism and marketing lean AP, books and academia lean Chicago, and then stop relitigating it.

Small words in titles decide most title case arguments

The contested territory.

Articles are easy: a, an, and the stay lowercase everywhere except first or last position, and all guides agree. Coordinating conjunctions like and, but, or, and nor stay down too. The fights happen over prepositions and over two-letter words that moonlight as other parts of speech.

Consider 'up' in 'Look Up the Answer' versus 'Walking up the Hill'. In the first, up belongs to the phrasal verb look up, and both AP and Chicago capitalize it. In the second it's a plain preposition and stays down in Chicago. This is why small words in titles can't be resolved by a lookup table alone, and why any automatic tool, this one included, works from a fixed word list that gets the common cases right and leaves phrasal verbs for your judgment.

One headline worked through the title case rules

AP, Chicago, and the tool.

Input: 'the art of working from home'. Chicago output: 'The Art of Working from Home', with of and from lowercase as prepositions and The capitalized only because it leads. AP output: 'The Art of Working From Home', identical except From, promoted for having four letters.

Run the same string through the Title Case Converter and you get 'The Art of Working from Home', matching Chicago on this headline, because from sits on the tool's minor-word list. Feed it 'a room with a view' and you get 'A Room With a View', since with isn't on the list, which happens to match AP. Knowing where your tool's list sits relative to your style guide takes one test headline, and after that every conversion is predictable.

The title case errors editors flag first

Learn them once.

A handful of mistakes account for nearly all title case corrections:

  • Lowercasing the last word. 'What Dreams Are Made of' is wrong in every guide; first and last words always get capitals, even prepositions.
  • Lowercasing short verbs. Is, Are, Be, and Was are verbs and take capitals despite their size; 'Why Remote Work is Here to Stay' fails on is.
  • Capitalizing every word indiscriminately. 'The Best Way To Save For A House' reads as amateur; that's Capital Case wearing a title case costume.
  • Inconsistent hyphenated compounds. Most guides want 'State-of-the-Art Design', capitalizing the significant parts while of and the stay down.
  • Mixing AP and Chicago across one site, so 'Working From Home' and 'Living with Less' sit two posts apart.

Keeping title case consistent across a whole site

Process beats memory.

Write the decision down once: a single line in your style doc saying 'headlines use AP title case' or 'Chicago, always' ends the per-headline debates. Then make the converter part of the publishing path, so every H1 and email subject passes through it before going live. Consistency produced by a pipeline survives staff turnover; consistency produced by memory doesn't.

For legacy content, resist the urge to fix everything at once. Convert titles as posts get updated for other reasons, and prioritize the pages that appear in navigation menus and search results, since those are the places where a mixed style is visible side by side.

When title case is the wrong choice, and which tool to open

Boundaries of the job.

Plenty of respected publications skip title case entirely and run sentence-style headlines, capitalizing only the first word, a look that reads as modern and works especially well for long, conversational titles. If that's your house style, the Case Converter has a Sentence case card, along with Capital Case and the programmer formats for slugs and identifiers.

Length is the other half of headline quality. A perfectly capitalized title that truncates in search results still fails, so check it against the 60 character title tag budget with the Character Counter. And when the headline sits atop a long article, the Reading Time Calculator tells you what estimate to print beside it.

Try it now

Open Title Case Converter

The tool is one click away. No sign up, no upload, no payment.

Open Title Case Converter