Text case converter

How to use it

1. Type or paste your text into the box.
2. Tap a case — UPPERCASE, lowercase, Title Case, Sentence case, camelCase, snake_case or kebab-case.
3. Hit Copy to put the result on your clipboard.

Title case is a style-guide choice, and the guides disagree

There is no single rule for title case. Chicago lowercases prepositions whatever their length, printing A Room with a View; AP capitalises any word of four letters or more, making it A Room With a View; APA lowercases words of three letters or fewer. This converter capitalises every word, which is predictable but matches no house style exactly - so proofread the output against whichever guide you are writing to.

Two things always need a human eye. Case conversion flattens acronyms and proper nouns, because nothing in plain text marks them as special: NASA becomes Nasa, iPhone becomes Iphone. And case is locale-dependent. In Turkish, lowercase I is the dotless ı and uppercase i is the dotted İ, so the standard mapping used here - correct for English - quietly misspells Turkish words.

camelCase and snake_case are language conventions, not decoration

Each language enforces its own. Python’s PEP 8 wants snake_case for functions and variables with PascalCase classes, and Rust splits the same way while reserving SCREAMING_SNAKE_CASE for constants. JavaScript and Java use camelCase for variables and methods, PascalCase for classes. CSS is kebab-case throughout, custom properties included. Go goes furthest: a capital first letter exports an identifier from its package, so case there is compiler-visible, not cosmetic.

The trap is round-tripping. Word boundaries have to be guessed, and consecutive capitals are ambiguous: parseHTMLDocument becomes parse_html_document, which converts back as parseHtmlDocument - a different identifier that will not resolve. Check anything holding an acronym or a digit by hand. Kebab-case has a harder limit still, since a hyphen is the subtraction operator: user-name is fine in CSS, a filename or a URL, but in JavaScript it parses as user minus name.

Questions