Case Converter

Change the case of any text

Paste your text, pick a case, and the converted version appears immediately. The copy button takes the whole result, and your original stays in the box above so you can try another case without pasting again.

Each option in the picker is written in the case it produces, so there is no legend to read: snake_case looks like snake_case, aLtErNaTiNg looks like itself.

Everything runs in your browser. Nothing is uploaded, stored or logged, and the text is never written into the page address.

The eleven cases

UPPERCASE and lowercase do exactly what they say to every letter.

Title Case capitalizes the significant words and leaves the small ones alone — for headlines, article titles, book and film names.

Sentence case capitalizes the first word of each sentence and nothing else. This is the one for body text.

camelCase, PascalCase, snake_case, kebab-case and CONSTANT_CASE are the programmer cases: the same words, joined without spaces in five different conventions.

aLtErNaTiNg flips between lowercase and capitals letter by letter. iNVERSE swaps the case of whatever you already have — the fix for a paragraph typed with Caps Lock on.

Title case is not “capitalize everything”

This is the conversion people get wrong most often, and it is worth knowing the rule.

In title case, short function words stay lowercase: a, an, and, as, at, but, by, for, if, in, nor, of, on, or, per, the, to, via, vs. Everything else is capitalized. So:

the lord of the rings → The Lord of the Rings

Not “The Lord Of The Rings”, which is what you get from a tool that simply capitalizes every word — and what makes a headline look machine-made.

The first and last word are always capitalized however short they are. “A Room of One’s Own” keeps its opening “A”, and a title ending in “to” ends in “To”.

Style guides disagree at the edges, mostly about prepositions of four letters or more. This tool follows the common newsroom convention: short prepositions down, longer ones up, so “from” and “with” are capitalized. If your house style differs, the two or three affected words are quick to fix by hand.

What Sentence case can and cannot know

Sentence case lowercases the text and then capitalizes the first letter of each sentence, where a sentence begins after ., !, ? or an ellipsis. Opening and closing quotation marks are stepped over, so "hello. it works" comes back as "Hello. It works".

Two things it cannot get right, because no rule can without a dictionary:

Abbreviations ending in a period. “Approx. 3pm” looks like two sentences to any punctuation rule.

Proper nouns. Names, places and brands are lowercased along with everything else. There is no way to tell “Paris” from “paris” from the text alone.

Both are quick to repair by eye, which is why this tool rewrites everything and lets you fix a handful of words rather than leaving a whole paragraph shouting.

Acronyms get flattened, on purpose

Title and Sentence case lowercase the text before recapitalizing it, so NASA becomes Nasa.

That is a deliberate trade. The alternative — leaving every all-caps word alone — sounds better until you paste a heading that is entirely in capitals, which is the single most common reason anyone opens a case converter. Under that rule nothing would change at all.

Rewriting everything and repairing two acronyms by hand is the better default. If your text is mostly acronyms, convert it with UPPERCASE or lowercase first and capitalize the sentences yourself.

The programmer cases

These five split your text into words and rejoin them without spaces. The splitting is smarter than “break on spaces”: it also breaks at a lowercase-to-capital boundary and handles runs of capitals correctly, so an existing identifier converts cleanly between conventions.

getHTTPResponse → get_http_response → getHttpResponse

Note what did not happen: HTTP was treated as one word, not four. A naive splitter produces get_h_t_t_p_response.

Punctuation that separated words is dropped, since it cannot survive in an identifier: Hello, World! Again becomes hello-world-again.

Which convention to use is usually decided for you by the language. JavaScript and Java use camelCase for variables and PascalCase for classes; Python and Rust use snake_case; CSS classes and URLs use kebab-case; constants in most languages use CONSTANT_CASE.

Your line breaks survive

Every conversion runs line by line and rejoins the result with the breaks it started with, including Windows line endings.

This matters more than it sounds. Paste a column of forty product names, choose kebab-case, and you get forty URL slugs — one per line, ready to paste into a spreadsheet column. Most converters join everything into a single string, which turns a two-second job into a manual one.

Blank lines between paragraphs are preserved too, and Title Case treats each line as its own title rather than running the rule across the whole document.

Why not use a spreadsheet or an editor?

You can, and for a one-off it may be faster.

Spreadsheets offer UPPER(), LOWER() and PROPER(). The catch is PROPER(): it capitalizes every word, including the small ones, so it produces “The Lord Of The Rings” and cannot do sentence case at all.

Code editors usually have upper and lower case commands, and often a plugin for the programmer cases. What they rarely have is title case with a real word list, or the ability to run a conversion down forty lines and see the result before committing to it.

Non-Latin text

Words are identified with Unicode letter and digit rules rather than A–Z, so accented Latin, Greek, Cyrillic and similar scripts split and capitalize on the same rules as English.

Scripts without upper and lower case — Chinese, Japanese, Arabic, Hebrew, Thai — pass through unchanged by the case conversions, which is correct: there is no capital form to convert to. The programmer cases still work on them, joining words on the punctuation and spacing that separates them.

Frequently asked questions

How do I fix text that was typed in all caps?

Choose Sentence case for prose or Title Case for a heading. Both lowercase the whole text first and then put the capitals back where they belong, which is why they repair shouting text rather than leaving it as it is.

Why does Title Case leave some words lowercase?

Because that is what title case means. Short words — a, an, and, at, by, for, in, of, on, or, the, to — stay lowercase unless they open or close the title. So "the lord of the rings" becomes "The Lord of the Rings", not "The Lord Of The Rings".

Why did it turn NASA into Nasa?

Title and Sentence case lowercase everything before recapitalizing, because most text arriving here is being rescued from all-caps. Nothing in the text says whether NASA is an acronym or just a shouted word, so acronyms get flattened along with the rest. Fix those few by hand afterwards.

What is the difference between camelCase, PascalCase and snake_case?

They are the same words joined differently. camelCase lowercases the first word and capitalizes the rest (userFirstName). PascalCase capitalizes all of them (UserFirstName). snake_case lowercases everything and joins with underscores (user_first_name); kebab-case uses hyphens; CONSTANT_CASE is snake_case in capitals.

Does it keep my line breaks?

Yes. Every conversion runs line by line, so a list stays a list. Paste a column of names, choose snake_case, and you get a column of identifiers back — not one long run-on string.

Will it handle accented or non-Latin text?

Yes. Words are split using Unicode letter rules rather than A–Z, so French, German, Spanish, Greek, Cyrillic and similar text converts on the same rules as English.

Is my text uploaded anywhere?

No. Everything runs in your browser, nothing is stored or logged, and the text is deliberately never written into the page address.