When to Use Title Case vs. Sentence Case vs. All Caps
Title Case (Capitalizing Most Major Words) is conventional for headlines and titles. Sentence case (capitalizing only the first word and proper nouns) is conventional for body text and most everyday writing. ALL CAPS is conventionally reserved for strong emphasis or specific stylistic contexts (acronyms, warnings), and using it broadly is generally read as shouting in most written contexts.
Each case style carries a real, widely understood convention, and using the wrong one for a given context can subtly undermine how professional or readable a piece of text feels.
Title Case
Used conventionally for headlines, article titles, and book titles — the specific rules for which words get capitalized (major words yes, most short articles and prepositions no) vary slightly between style guides, which is why title case converters sometimes offer multiple style options.
Sentence case
The standard for body text, most emails, and everyday writing — only the first word of a sentence and proper nouns are capitalized. This is generally the most readable format for longer text, since readers are most accustomed to it.
ALL CAPS
Conventionally reserved for acronyms, short warnings, or deliberate strong emphasis — using it for anything longer than a short phrase is widely read as shouting and can reduce readability, since all-caps text is measurably harder to read quickly than mixed-case text for most readers.