The case styles
"Case" refers to how letters and word boundaries are formatted. The everyday styles are UPPERCASE, lowercase, Title Case (each major word capitalised) and Sentence case (only the first letter of each sentence). Programmers also use camelCase, snake_case and kebab-case for names with no spaces.
This converter applies each transformation to your exact text at once, so you can copy whichever form a document, headline or codebase needs.
Worked example
The phrase "order id" in code styles:
Title case vs sentence case
Title Case capitalises the first letter of each significant word — this tool capitalises every word for simplicity, which suits headlines. Sentence case capitalises only the first letter after each sentence-ending mark, matching how normal prose is written. Choose title case for headings and button labels, and sentence case for body copy and UI text, which most modern style guides prefer.
Which case does each language expect?
Naming conventions aren't arbitrary — most languages and frameworks publish style guides, and matching them makes your code read the way other people's code does. The common defaults:
| Context | Variables / functions | Types / classes | Constants |
|---|---|---|---|
| JavaScript / TypeScript | camelCase | PascalCase | UPPER_SNAKE_CASE |
| Python (PEP 8) | snake_case | PascalCase | UPPER_SNAKE_CASE |
| Ruby | snake_case | PascalCase | UPPER_SNAKE_CASE |
| Go | camelCase (private) / PascalCase (exported) | PascalCase | PascalCase |
| CSS classes | kebab-case (BEM uses block__element--modifier) | ||
| SQL columns | snake_case (unquoted identifiers are case-insensitive) | ||
| URLs & file names | kebab-case — lowercase, hyphen-separated, no spaces | ||
When you cross a boundary — say a Python API (order_id) feeding a JavaScript front-end (orderId) — pick one convention for the wire format and convert at the edge, rather than mixing both throughout your code.
Edge cases this tool handles (and a few it can't)
Converting case sounds trivial until real text arrives. A few things worth knowing:
- Acronyms.
HTTPSConnection→https_connectionis usually what you want, butparseURLcan becomeparse_u_r_lin naive converters. This tool splits on the lower→upper boundary, so check acronym-heavy names by eye. - Numbers.
user2FAandaddress2keep their digits attached to the adjacent word — there's no universal rule, so confirm the result matches your project's style. - Accents and non-Latin scripts. Case conversion respects Unicode where the browser does, but for URL slugs you'll usually want to transliterate (é → e) — that's a job for the slug generator, not a case converter.
- The Turkish "i". In Turkish locale, uppercasing
igivesİ(dotted), notI. This tool uses the default (invariant) mapping, which is the safe choice for code identifiers.
Sentence case vs Title Case for headings
For user-facing copy the trend has moved decisively toward sentence case. Apple's Human Interface Guidelines, Google's Material Design and the GOV.UK style guide all recommend sentence case for buttons, menus and titles, because it's faster to read, looks less shouty, and avoids the genuine ambiguity of which words to capitalise in title case. Reserve Title Case for proper nouns, book and article titles, and contexts where a house style demands it. If you're unsure, sentence case is the safer default in 2026.