Tool 016 / text / free / runs locally
Case Converter
Case Converter is a free, no-signup tool that changes text to UPPERCASE, lowercase, Title Case, Capitalized Case, or Sentence case, and turns phrases into camelCase, PascalCase, snake_case, CONSTANT_CASE, or kebab-case identifiers. Paste your text, click a case, and copy the result. It runs entirely in your browser, so nothing is uploaded.
THE QUICK BROWN FOX
How it works
This converter transforms your text into one of ten cases. Five keep it as prose: UPPERCASE, lowercase, Title Case, Capitalized Case, and Sentence case. Five turn it into an identifier: camelCase, PascalCase, snake_case, CONSTANT_CASE, and kebab-case. It is built for the everyday jobs of cleaning up headings, fixing text typed with caps lock on, and reformatting variable names. Conversion happens in your browser as you type, with nothing uploaded.
Title Case follows the rule AP and Chicago share: capitalise the main words, and keep articles, coordinating conjunctions, and short prepositions (a, an, the, and, but, or, of, in, on, to, and similar) lowercase unless they open or close the title or follow a colon. Each line is treated as its own title, so a pasted list of headings converts in one pass. Capitalized Case is the simpler style that capitalises every word. Sentence case capitalises the first letter of each sentence and each line, and the pronoun I.
The prose cases leave deliberate capitals alone when your text is otherwise mixed case: a word with a capital after its first letter, such as NASA, API, iPhone, or JavaScript, is kept as typed. If the whole input is in capitals, nothing about it was deliberate, so it is lowercased first and then recased.
The identifier cases first split your text into words at spaces, punctuation, hyphens, and underscores, at lowercase-to-uppercase boundaries, and at the end of a run of capitals. That is what lets you paste myVariableName and get my_variable_name, or paste XMLHttpRequest and get xml_http_request rather than xmlhttp_request.
How to use it
- Type or paste your text into the input box.
- Click the case you want from the row of buttons.
- Read the converted text in the output box on the right.
- Click Copy to grab the result.
Worked examples
Input: the lord of the rings: the return of the king -> Title Case
Output: The Lord of the Rings: The Return of the King
Small words stay lowercase, except the one that opens the subtitle after the colon.
Input: XMLHttpRequest -> snake_case, then CONSTANT_CASE
Output: xml_http_request, then XML_HTTP_REQUEST
The capital run XML is split from Http before the words are rejoined.
Edge cases and limits
- Title Case uses one fixed list of short words. Style guides disagree at the edges (AP capitalises prepositions of four or more letters, Chicago lowercases every preposition), so check a heading against your house style if it matters.
- Sentence case finds sentence starts from . ! and ? followed by a space, and from line breaks. It does not know proper nouns, so names in the middle of a sentence come out lowercase unless they contain a deliberate capital such as iPhone.
- Keeping deliberate capitals means a single word written in capitals for emphasis, in otherwise normal text, stays in capitals. Convert to lowercase first if you want it gone.
- Identifier cases drop every character that is not a letter or digit, so punctuation and apostrophes disappear. Accented letters are kept, so use the Slug Generator if you need plain ASCII.
Common mistakes
- Using Capitalized Case for a headline. Capitalising of, the, and to is the most visible sign of an automated title.
- Converting text with important punctuation to snake or kebab case and losing that punctuation in the identifier.
- Assuming Sentence case fixes proper nouns. It only handles the first letter of each sentence and the pronoun I.
- Pasting a whole paragraph to get a variable name. Identifier cases join everything into one long identifier, so convert the phrase you need, not the sentence around it.
Frequently asked questions
What is the difference between Title Case and Sentence case?+
Title Case capitalizes the main words of a heading and keeps short words like a, of, and the lowercase unless they come first or last. Sentence case capitalizes only the first letter of each sentence, plus the pronoun I, which suits body text. Capitalized Case capitalizes every word.
How does camelCase conversion handle spaces and symbols?+
We split your text into words at spaces, punctuation, hyphens, underscores, and existing capital boundaries, so XMLHttpRequest becomes XML, Http, Request. Then we lowercase the first word, capitalize each following word, and join them with no separators.
Is there a length limit?+
There is no fixed limit. Conversion runs locally in your browser, so very large blocks of text work fine on modern devices.
How do I convert uppercase text to lowercase?+
Paste the text and click lowercase to change every letter, or Sentence case to get normal prose back with capitals at the start of each sentence. Sentence case is usually what you want for text typed with caps lock on.
Does Title Case keep words like of and the lowercase?+
Yes. Articles, coordinating conjunctions, and short prepositions stay lowercase unless they are the first or last word or follow a colon, so the lord of the rings becomes The Lord of the Rings. Use Capitalized Case if you want every word capitalised.
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