Case Converter

How to change the case of text

1. 1

   Add text

   Type or paste plain text, or import a local .txt file.

2. 2

   Choose a mode

   Pick one general text mode or one naming format.

3. 3

   Convert and check

   Press Convert, check the output, then copy or download it.

General text modes

These modes keep every line break, space, punctuation mark and number. A word is a run of letters and numbers, and an apostrophe inside it (“don’t”) does not split it.

• lowercase and UPPERCASE. Use the browser’s built-in case rules, which do not depend on your language. Some letters change length: the German “ß” becomes “SS” in uppercase.
• Sentence case (approximate). Lowercases everything, then capitalises the first letter of each sentence. A sentence starts at the beginning of the text, at the start of every line, and after a full stop, question mark, exclamation mark or ellipsis followed by a space. A sentence that starts with a number is left as it is. Abbreviations such as “e.g.” can start a false sentence, and proper nouns, acronyms and “I” come out in lowercase, so check the result.
• Title Case. Title-case conventions vary between style guides, so this uses one simple English rule set. Words are lowercased, then each is capitalised except these minor words: a, an, the, and, but, for, nor, or, so, yet, as, at, by, in, of, off, on, per, to, up, via, vs. The first and last word of every line, the first word after a colon, and the first part of a hyphenated word are always capitalised. A number counts as a word. Names and acronyms are lowercased first, so check the result.
• Capitalize Each Word. Capitalises the first letter of every word, including short ones, and lowercases the rest. “Well-known” becomes “Well-Known”.
• Toggle Case. Swaps every letter that has a one-character uppercase and lowercase form. Other characters, such as numbers, symbols, Chinese or Japanese text, and letters like “ß” whose uppercase is longer, stay as they are.

Naming formats

Each line is converted on its own into one name, and line breaks are kept. Spaces, punctuation, symbols and emoji separate words and are dropped, as are spaces at the ends of the line. Apostrophes inside a word are dropped without splitting it, so “don’t” becomes “dont”.

• Where words split. At separators, where a lowercase letter or number is followed by a capital (“fooBar”, “v2Beta”), and before the last capital of an acronym (“HTMLParser” becomes HTML and Parser). Letters next to numbers stay together (“utf8”).
• The five formats. camelCase starts in lowercase, PascalCase capitalises every word, snake_case and kebab-case are lowercase with underscores or hyphens, and CONSTANT_CASE is uppercase with underscores. Acronyms follow the format, so “HTMLParser” becomes htmlParser.
• Accents and other scripts. Accents are kept and nothing is transliterated: “Café Crème” becomes café_crème. Scripts without capitals, such as Chinese, are kept as they are.
• Lines with no words. A line with no letters or numbers becomes an empty line. The summary says how many lines that happened to.

Output, Undo and saving

• The original stays put. The output is made only when you press Convert. If the text or mode changes afterwards, the output is marked out of date until you convert again.
• Use Output as Input. Replaces the original with the converted text so you can convert it again. Undo brings the previous original back, also after Clear, Import or Load Example.
• Line breaks. The text boxes always show line breaks the same way. If you import a file that uses Windows (CRLF) line breaks, Copy Output and Download .txt use them too.
• Right-to-left text. It is kept as it is, and each box takes its direction from the first letter. Text is shown as plain text, never as HTML.

Limits

maximum text size

2 MB

maximum lines

50,000

Longer texts are refused with a message rather than cut. Converting runs in a background thread (a Web Worker) so the page stays responsive.

Frequently asked questions