The AP Stylebook is the standard reference for American newspapers, digital news outlets, and broadcast journalism. Its title case rules capitalize major words while lowercasing articles, coordinating conjunctions, and prepositions of any length.
AP Style title case capitalizes the first letter of every major word in a headline or title. Articles such as "a," "an," and "the," coordinating conjunctions such as "and," "but," and "or," and all prepositions are lowercased unless they begin or end the title.
The Associated Press introduced this standard to create visual consistency across wire service copy used by thousands of news organizations. It remains the most widely adopted style guide in American journalism.
AP Style is the house style for most American newspapers, television networks, and online news publications. If you are writing for a journalistic outlet, submitting press releases, or creating content that will be edited by journalists, AP Style is the expected format.
Public relations professionals and corporate communications teams often follow AP Style because it aligns with the preferences of the journalists they pitch. Using AP Style in press releases improves the odds that copy will be used with minimal editing.
In AP Style, prepositions are always lowercase, regardless of their length. This distinguishes it from Chicago Style, which only lowercases short prepositions of four letters or fewer.
The first word and the last word of any headline are always capitalized, even if they would normally be lowercase. Proper nouns are always capitalized throughout the headline.
The key difference between AP Style and Chicago Style is the treatment of prepositions. Chicago lowercases only short prepositions of four letters or fewer, while AP lowercases all prepositions regardless of length.
Chicago Style is the standard for book publishing, while AP Style dominates journalism. Knowing which context you are writing for tells you which convention to follow.