Case Converter

Convert text into thirteen cases at once, from Title Case to snake_case, with words split correctly across acronyms, apostrophes and every script.

Overview

Case conversion rewrites the same words under a different convention. Prose has four: all lower, all upper, a capital on every word, and a capital on every sentence. Code has more, because an identifier cannot contain spaces, and every language settled on its own way of marking where one word ends and the next begins: userName, user_name, user-name. The hard part of converting between them is finding the words, and this tool does that once for all seven code conventions, so they cannot disagree.

Web interface

Type or paste into the field. All thirteen results update as you type, grouped into prose, code and two for fun, and each is labelled in its own style. Copy copies one result, and is switched off for a result with nothing in it. The line under the field counts characters, words and lines; words are counted by the rules below, so getXMLHttpRequest is four. The dice in the field loads a random example, Clear empties it.

Conversions

The prose cases change letters only, so punctuation, spacing and line breaks come through as they were. For don't touch the café's espresso machine:

Title Case capitalises every word and lower cases the rest of it, so iPhone becomes Iphone and NASA becomes Nasa; it follows no style guide's list of small words. Sentence case lower cases everything, I and names included, then capitalises the first letter of each sentence: at the start, after ., !, ? or … and a space, and on every new line, so a list gets a capital on each line. Opening quotes, brackets and the Spanish ¿ and ¡ are stepped over to reach the letter.

The code cases split the text into words first and join them again. For getXMLHttpRequest handler_v2:

An acronym becomes an ordinary word in camelCase and PascalCase, Xml rather than XML, which is what makes the result convert back cleanly. The two for fun: l33t replaces a b e g i l o s t z with 4 8 3 9 1 1 0 5 7 2 and leaves every other character alone, and mOcKiNg alternates lower and upper case letter by letter, starting lower.

Where words are split

Converting line by line is what makes a column of field names useful: paste first name, last name and email address on three lines and every code case comes back as three lines, firstName, lastName, emailAddress.

A separator is not remembered. path/to/file becomes pathToFile, and path/case turns that back into path/to/file because it puts slashes in, not because it knew they were there.

Other languages

Accented and non-Latin letters are letters. café stays whole, also when the accent arrives as a character of its own after the e, as it does in text copied from macOS file names, and so does Hindi नमस्ते, whose vowel signs are separate characters of that kind. Scripts without case, such as Hindi, Chinese or Arabic, pass through the case changes as they are and are only split and joined.

Case follows Unicode's rules, which belong to no particular language:

• German ß has no single capital in those rules, so upper case turns Größe into GRÖSSE, and lower case leaves ß as it is.
• Greek sigma is written ς at the end of a word, so ΟΔΟΣ becomes οδος.
• Turkish is the exception that does not come out right: lower case turns İ into i followed by a combining dot above, and upper case turns i into I rather than İ. Turkish rules would give the wrong result for every other language.

No API

Privacy

Nothing leaves the browser. The text is converted on the page as you type, nothing is stored or sent, and Copy writes to the clipboard only when you press it.