Case Converter

Paste text into the case converter and click a button to convert it to upper case, lower case, Title Case or Sentence case, or to a programming style such as camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE or dot.case. There are also alternating and inverse cases for fun. Programming styles convert each line separately, so a list of names stays a list. Nothing leaves your browser.

How to use it

Type or paste your text, then click a case. The chosen button stays highlighted and the result updates as you keep typing. Copy result puts the output on your clipboard, and Use result as input lets you chain conversions. Text up to 2 MB is supported.

What each case does

• UPPER and lower change every letter, using Unicode rules, so straße becomes STRASSE.
• Title Case capitalises each word. Short words such as of, the and and stay lower case unless they are first, last or follow a colon; untick the option to capitalise every word.
• Sentence case lowers everything, then capitalises the first letter of each sentence and line, and the word I. Abbreviations such as e.g. and i.e. do not start a new sentence.
• camelCase and PascalCase join words with capitals: userId, UserId.
• snake_case, kebab-case, CONSTANT_CASE and dot.case join lower or upper case words with _, - or ..
• aLtErNaTiNg switches case letter by letter and iNVERSE swaps the case of each letter.

How words are found

For programming styles the tool splits text on spaces, punctuation, underscores and hyphens, and also at case changes inside a word. XMLHttpRequest becomes the words XML, Http and Request, so its snake_case form is xml_http_request. Apostrophes are dropped, so don't stop becomes dontStop. Digits stay attached to the word they follow.

Tips

To rename many variables at once, paste one name per line and pick the target style; blank lines are kept, so the output lines up with the input. Run Sentence case on text that was typed with Caps Lock on, then fix proper nouns such as product names by hand.

For server admins

Naming rules differ: environment variables use CONSTANT_CASE, Kubernetes resource names and DNS labels need kebab-case, Python and Ansible variables use snake_case and Java or JavaScript uses camelCase. On the shell you can do the simple cases with tr or Bash:

echo 'db host' | tr '[:lower:] ' '[:upper:]_'   # DB_HOST
v='Server Name'; echo "${v,,}"                 # server name
echo 'my_var_name' | sed -E 's/_(.)/\U\1/g'      # myVarName (GNU sed)

Case Converter at a glance

Related tools: Word Counter · URL Encoder, Decoder and Parser.

Official documentation (checked 9 October 2026): MDN: String.prototype.toUpperCase() · PEP 8: Style Guide for Python Code (naming conventions)

Frequently asked questions