Case Converter

The programming cases and where each belongs

camelCase starts lowercase and capitalises each subsequent word. It is the convention for variables and functions in JavaScript, Java and Swift.

PascalCase capitalises the first word too, and is used for classes, types and components across most languages, including React components and C# methods.

snake_case joins lowercase words with underscores. It is the Python and Ruby convention for variables and functions, and the usual convention for database column names.

kebab-case joins lowercase words with hyphens. It is what URLs, CSS class names and HTML attributes want, and is the correct format for a blog post slug — search engines treat hyphens as word separators and underscores as joiners, which is why a hyphenated slug is preferable.

CONSTANT_CASE is uppercase with underscores, used for constants and environment variables almost universally.

The converter splits on spaces, hyphens, underscores and dots, and also detects existing camelCase boundaries — so converting getUserName to snake_case correctly yields get_user_name rather than getusername.

Title case is not one rule

There is no single correct title case, which is why automated versions disagree with each other. The main style guides differ on which short words stay lowercase and where the exceptions lie.

Chicago style lowercases articles, coordinating conjunctions and prepositions regardless of length, but capitalises the first and last word whatever they are. AP style capitalises prepositions of four letters or more. APA capitalises words of four letters or more.

This tool applies the simple rule of capitalising every word, which is right for headlines in many house styles and wrong in others. For anything published under a specific style guide, treat the output as a starting point and adjust the short words by hand.

Sentence case — capitalise the first word and any proper nouns — is increasingly the house style for web headings, and is easier to get right automatically because there is only one rule.

Fixing text that came out wrong

The most common rescue job is text typed with caps lock on. Converting to lowercase and then to sentence case recovers most of it; proper nouns will need fixing by hand, since no algorithm can reliably distinguish a name from a common word.

Text pasted from a PDF or a design tool frequently arrives in all caps because the capitals were applied as styling rather than typed. Lowercasing it recovers the underlying words, though again the proper nouns are lost.

Alternating case has one legitimate use, which is the mocking tone convention on social media. It has no other.

What the converter does not change

Punctuation, numbers and spacing are preserved in the case-only transformations. The programming cases necessarily discard spacing, since that is the point of them.

Accented and non-Latin characters are handled by the browser's own Unicode-aware case mapping, so ü uppercases to Ü and Greek or Cyrillic text converts correctly. A handful of languages have case rules that no general converter gets right — Turkish dotted and dotless i being the classic example — so check anything in those languages by eye.

Text is processed entirely in the page. Nothing is sent to a server, which matters if you are converting variable names from a private codebase.