Case Converter — UPPER, lower, Title, camelCase, snake_case & More
Switch text between twelve cases in one click, from UPPER and Sentence case to camelCase, snake_case and kebab-case.
121 characters · 4 lines
Title Case here follows Chicago style (short words like “of”, “the”, “and” stay lowercase). For APA, MLA or AP rules use the title case converter.
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This free case converter changes text between UPPER CASE, lower case, Title Case, Sentence case and the programmer cases (camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE and dot.case) with one click. Paste a paragraph someone typed with Caps Lock on, a column of database fields, or a heading that needs fixing, pick the case, and copy the result.
The programmer cases are where most converters go wrong. This one splits words at spaces, underscores, hyphens and dots, and also at case changes inside a word, so getHTTPResponseCode becomes get_http_response_code rather than gethttpresponsecode. Each line converts separately, so a pasted list stays a list. It handles accented and non-Latin letters, but it does not know grammar: Sentence case capitalizes after a full stop and fixes a lone “i”, but it cannot tell that “paris” is a proper noun.
How to use
- Type or paste your text into the box. A sample is already there so you can see how it works.
- Click a case button. The result below updates immediately and keeps updating as you edit the input.
- For camelCase, snake_case and the other code styles, put one name per line to convert a whole list.
- Copy the result, download it as a text file, or click Use as input to chain another conversion.
Frequently asked questions
How do I change text from all caps to lowercase?
Paste the text and click lower case to get everything in small letters, or Sentence case to keep a capital at the start of each sentence, which is usually what you want for text typed with Caps Lock on. Sentence case also capitalizes the word “I”, but names and places stay lowercase, so check those before you publish.
What is the difference between camelCase and PascalCase?
Both join words without spaces and capitalize the start of each word. camelCase keeps the first letter lowercase (firstName), PascalCase capitalizes it too (FirstName). JavaScript and Java use camelCase for variables and functions and PascalCase for classes; React requires PascalCase for component names.
When should I use snake_case vs kebab-case?
snake_case (words joined by underscores) is the convention for Python variables and functions, Ruby, and most SQL column names. kebab-case (hyphens) is used in URLs, CSS class names and command-line flags. kebab-case cannot be used for variable names in most languages, because the hyphen is read as a minus sign.
What does Title Case do here?
It capitalizes the main words and keeps short articles, conjunctions and prepositions lowercase (“The Lord of the Rings”), following the Chicago Manual of Style. If you need APA, MLA or AP rules specifically, use the title case converter, which applies each guide's own list of minor words.
Does it work with accented letters and other alphabets?
Yes. Letters such as é, ñ, ü, Greek and Cyrillic change case correctly, and German ß becomes SS in upper case. Scripts without upper and lower case, such as Chinese or Arabic, pass through unchanged. Identifier cases use language-neutral rules, so a browser set to Turkish does not turn “id” into “İD”.
Which case to use where
• camelCase: JavaScript, TypeScript and Java variables and functions; JSON keys in many APIs.
• PascalCase: class names in most languages, React components, C# methods and properties, TypeScript types.
• snake_case: Python variables and functions (PEP 8), Ruby, Rust variables, PostgreSQL and MySQL column names.
• CONSTANT_CASE: constants in most languages and environment variables (DATABASE_URL).
• kebab-case: URL slugs, CSS classes, HTML attributes, npm package names, command-line options.
• dot.case: configuration keys (Java properties, some logging and i18n systems).
• Title Case: headings and titles in English; style guides differ on which small words stay lowercase.
• Sentence case: body text, UI labels and buttons in most design systems (Google's Material and Apple's guidelines both use it for most labels).
How words are split for code cases
To build camelCase or snake_case from arbitrary text, the converter first breaks it into words. Any character that is not a letter or digit is a boundary, so spaces, underscores, hyphens, dots and slashes all separate words. Apostrophes are removed rather than treated as boundaries, so “don't” becomes dont, not don_t.
Inside a word, a boundary is placed where a lowercase letter or digit is followed by a capital (userId → user, Id) and where a run of capitals is followed by a capital-plus-lowercase pair (XMLHttp → XML, Http). That second rule is what keeps acronyms together, and it is why converting from one code case to another round-trips cleanly. Digits stay attached to the word before them, so version2Beta becomes version2_beta.
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