Case Converter: Uppercase to Lowercase, Title Case and Ten More

Paste text that came out in the wrong case and press the case you want. Twelve cases, from fixing caps lock to naming a variable; the counts update as you type.

Case converter

Paste, pick a case, copy. Everything runs in your browser.

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The Quick Brown Fox Jumps Over the Lazy Dog. It Was a Dark and Stormy Night!

76 characters · 16 words · 2 sentences · 1 lines

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Uppercase converter, lower case converter, and why you need both

Most text that needs a case converter arrived with caps lock on, was pasted from a form that shouted, or came from a headline that now has to be a sentence. Retyping is slow and introduces mistakes; changing the case is a mechanical job and this page does it mechanically. Uppercase converts every letter to capitals, which is what a heading, an acronym or a form field that insists on caps needs. Lowercase does the reverse and is the usual first step when a block of ALL CAPS text has to become readable again: convert to lowercase, then to sentence case, and the capitals reappear only where they belong.

Both directions are Unicode-aware. An é becomes É, a ß stays ß in uppercase because there is no single capital for it in most contexts, and letters outside the Latin alphabet, Greek or Cyrillic, follow their own case rules. The counts under the box, characters, words, sentences and lines, are updated as you type, so you can see whether a converted headline still fits a limit.

Title case converter: what gets capitalised and what does not

Title case is not "capitalise every word". Every style guide capitalises the first and last word and every noun, verb, adjective and adverb, and keeps the short function words small: articles (a, an, the), coordinating conjunctions (and, but, or, nor, for, yet, so) and short prepositions (at, by, in, of, on, to, up, via). This converter follows that rule, in the AP form where prepositions of four letters and more (with, from, over) stay capital. It also capitalises the word after a colon and both halves of a hyphenated word, so "star wars: the empire strikes back" becomes "Star Wars: The Empire Strikes Back" and "self-service" becomes "Self-Service". If you want every word capital regardless, small words included, that is Capitalized Case, the next button along.

Sentence case is the opposite job: everything lowercase except the first letter of each sentence, which the converter finds after a full stop, question mark or exclamation mark, and at the start of each line. A decimal point in a number and the dots in an abbreviation like e.g. are left alone, and the pronoun I stays capital.

Alternating case, inverse case, and the cases programmers use

Alternating case flips every letter in turn, lower then upper, and skips spaces and punctuation so the rhythm holds across words: the mocking meme text. Inverse case swaps whatever is there, capitals to small and small to capitals, which is the quickest repair for a paragraph typed with caps lock on, since the words that were meant to be capitalised come back capitalised.

The last five cases are for code. camelCase joins the words with each one after the first capitalised; PascalCase capitalises the first too; snake_case joins lowercase words with underscores; kebab-case uses hyphens, which is what a URL slug or a CSS class wants; CONSTANT_CASE is uppercase with underscores. The converter splits the input on spaces and punctuation, and also on the humps inside an existing identifier, so it converts between styles: userFirstName to user_first_name, USER_FIRST_NAME to user-first-name. Nothing is sent anywhere; the conversion runs in your browser and the text never leaves the page.

Every case, side by side

The twelve cases the converter offers, applied to one film title, from the same engine the buttons use. The third column says what each case is normally for.

Case	Example	Used for
UPPERCASE	THE LORD OF THE RINGS: RETURN OF THE KING	Every letter capital. Headlines, acronyms, shouting.
lowercase	the lord of the rings: return of the king	Every letter small. Undoes caps lock; the fix for ALL CAPS text.
Title Case	The Lord of the Rings: Return of the King	Capitalises the main words and keeps a, an, the, of, in and other short words small, except first and last. Headlines and titles.
Sentence case	The lord of the rings: return of the king	A capital at the start of each sentence, after a full stop, question mark or exclamation mark; the rest lowercase. Standalone "I" stays capital.
Capitalized Case	The Lord Of The Rings: Return Of The King	The first letter of every word capital, including the short ones. Also called Start Case.
aLtErNaTiNg CaSe	tHe LoRd Of ThE rInGs: ReTuRn Of ThE kInG	Lower, upper, lower, upper, letter by letter. The mocking SpongeBob meme text.
iNVERSE cASE	THE LORD OF THE RINGS: RETURN OF THE KING	Swaps every letter: capitals become small and small become capital.
camelCase	theLordOfTheRingsReturnOfTheKing	Words joined, first word small, each later word capitalised. JavaScript and Java variables.
PascalCase	TheLordOfTheRingsReturnOfTheKing	Words joined, every word capitalised. Class names in most languages.
snake_case	the_lord_of_the_rings_return_of_the_king	Lowercase words joined with underscores. Python, Ruby, database columns.
kebab-case	the-lord-of-the-rings-return-of-the-king	Lowercase words joined with hyphens. URLs, CSS classes, file names.
CONSTANT_CASE	THE_LORD_OF_THE_RINGS_RETURN_OF_THE_KING	Uppercase words joined with underscores. Constants and environment variables.

Case converter questions

How do I change from uppercase to lowercase without retyping?

Paste the text into the box, press lowercase, and copy the result. If the text is a paragraph, press Sentence case instead of lowercase and the first letter of each sentence comes back capital. Use the swap button to put the result back in the box and convert again.

Which words stay lowercase in title case?

Articles (a, an, the), coordinating conjunctions (and, but, or, nor, for, yet, so) and prepositions of three letters or fewer (at, by, in, of, on, to, up, via), unless they are the first or last word of the title or follow a colon. Longer prepositions such as with and from are capitalised, which is the AP rule; Chicago style would lowercase them too.

What is the difference between title case and capitalized case?

Capitalized Case capitalises the first letter of every word, small words included: "The Lord Of The Rings". Title Case keeps the small words lowercase: "The Lord of the Rings". Use Title Case for headlines and titles, Capitalized Case when a style or a form wants every word capital.

Does the converter handle accents and other alphabets?

Yes. It uses the Unicode case rules, so é becomes É, ñ becomes Ñ, and Greek or Cyrillic text converts the same way. Characters that have no case, digits, punctuation, emoji and most Asian scripts, pass through unchanged.

Can I convert camelCase to snake_case, or the other way?

Yes. The code cases split an identifier on its capital letters as well as on spaces, underscores and hyphens, so userFirstName becomes user_first_name and USER_FIRST_NAME becomes userFirstName. Acronyms are treated as one word: XMLHttpRequest becomes xml_http_request.

Is my text uploaded anywhere?

No. The conversion runs entirely in your browser; the page makes no request when you type or convert. You can load it once and use it offline.