Case Converter

Case conversion is one of those small tasks that eats disproportionate time when done by hand. Retyping twenty column headers into snake_case, fixing a document where Caps Lock was stuck, or turning a list of product names into URL slugs — each is a minute of tedious, error-prone editing. This case converter handles every convention — UPPERCASE, lowercase, Title Case, Sentence case, camelCase, PascalCase, snake_case, kebab-case and more — and updates the output as you type.

Prose cases in the case converter

UPPERCASE is for emphasis and, in a few conventions, for legal defined terms. Avoid it in body copy: it removes the word shapes readers rely on for fast scanning, and in most contexts it reads as shouting.

lowercase appears in design systems, brand marks and some modern style guides that reject capitalisation entirely.

Sentence case capitalises the first word and proper nouns only. It is the dominant convention for headings in technical documentation, including Google's and Microsoft's developer style guides.

Title Case capitalises principal words. It remains standard for article headlines, book titles and section headings in US publishing.

Programming cases for developers

Developers use the case converter to rename variables across conventions — paste a PascalCase class property and convert it to snake_case for a database migration, or flip a list of spreadsheet headers into kebab-case for URL slugs in one pass.

Word-boundary detection for accurate case conversion

The interesting part of case conversion is deciding where words begin. This case converter splits on spaces and punctuation, and it also splits existing camel and Pascal boundaries — so userAccountBalance correctly becomes user account balance before being re-cased into any other convention. Without that step, converting camelCase to snake_case would produce a single unbroken token.

Digit boundaries are treated conservatively: http2Server becomes http2_server rather than http_2_server, because splitting digits from letters breaks far more identifiers than it fixes.

Unicode correctness

Case mapping is not a simple ASCII offset. German ß uppercases to SS, Turkish i has a dotted capital İ and a dotless ı, and Greek has context-sensitive final sigma. This case converter uses the platform's Unicode-aware case mapping, so accented Latin, Greek and Cyrillic text converts correctly rather than producing mojibake.

Practical uses for the text case converter

A few scenarios where a case converter saves real time: fixing a mailing list where names arrived in mixed case, converting a batch of product codes to CONSTANT_CASE for an enum file, re-casing a bibliography of article titles to Sentence case for a reference list, or preparing a column of file names for a URL migration by converting them to kebab-case.

The undo stack means experimenting with a case is risk-free — you can always step back to the previous text without re-pasting. And because the entire conversion runs in the browser, sensitive data like customer lists, internal identifiers and unpublished copy never leave your device.