About the Case Converter
Zyff's case converter moves text between UPPERCASE, lowercase, Sentence case, Title Case and Capitalized Case, plus the identifier styles developers need — camelCase, PascalCase, snake_case, CONSTANT_CASE, kebab-case, Train-Case, COBOL-CASE, dot.case and path/case — and the playful ones, alternating, inverse and random. Its title casing follows a style guide you choose rather than capitalizing every word it meets: the naive version turns the cat in the hat into The Cat In The Hat, which no guide accepts, while Zyff gives you The Cat in the Hat. Conversion runs on Zyff's servers, in memory only, so no copy of what you paste is kept. Free, unlimited and no signup.
How to change text case online
Paste your text
Drop in a headline, a column of names, a list of product titles or a whole paragraph, up to 100,000 characters. Line breaks are preserved, so a pasted list comes back to you as a list.
Pick the case style
Choose UPPERCASE, lowercase, Sentence case, Title Case or Capitalized Case for prose, or camelCase, PascalCase, snake_case, CONSTANT_CASE, kebab-case, Train-Case, COBOL-CASE, dot.case and path/case for code and URL slugs. The result appears as you type.
Choose a title case rule
Title case is not one rule. Pick AP, APA, Chicago, MLA, New York Times or Wikipedia and the converter applies that guide's treatment of short words, rather than capitalizing everything and hoping for the best.
Review and copy
Scan the output for names and brand spellings no rule set can know about — a city typed as paris cannot be told from a surname — fix the handful that need a human, then copy the result or download it as a .txt file.
What the Case Converter does
Title case by style guide
AP, APA 7th, Chicago, MLA 9th, the New York Times list and Wikipedia genuinely disagree, so you choose the guide instead of accepting one opinion baked into the tool. The same headline, correct for whichever house style you write in.
Sentence case that finds sentences
Splitting on every period breaks on e.g., Dr., Inc., Fig. 3, 3.14 and example.com. Zyff reads the shape around each period instead, and uses the capital on the following word to tell “at 4 p.m. The deal closed” from “used in the U.S. and elsewhere”.
Acronyms and brand names kept intact
ALL-CAPS terms and names with an internal capital survive a pass untouched, so NASA does not come back as Nasa and iPhone does not come back as IPhone. Paste text with no lowercase at all and the protection switches itself off, because otherwise SHOUTING would convert to nothing.
Identifier styles for code and slugs
camelCase, PascalCase, snake_case, CONSTANT_CASE, kebab-case, Train-Case, COBOL-CASE, dot.case and path/case, all re-segmenting the input first — so userFirstName, user first name and user-first-name all convert to the same thing, in either direction.
Lists stay lists
Title and Sentence case run per line, so a pasted column of book titles comes back with each line capitalized on its own rather than only the first. Spacing, punctuation and blank lines are returned exactly as they arrived.
Cases your editor cannot do
Word's Shift+F3 cycles three options and Google Docs offers four; neither knows AP from Chicago, and neither will hand you snake_case or a URL slug. That gap is the reason this tool exists.
At a glance
| Prose styles | UPPERCASE, lowercase, Sentence case, Title Case, Capitalized Case |
|---|---|
| Identifier styles | camelCase, PascalCase, snake_case, CONSTANT_CASE, kebab-case, Train-Case, COBOL-CASE, dot.case, path/case |
| Other styles | aLtErNaTiNg cAsE, iNVERSE cASE, RaNDoM cAsE |
| Title case guides | AP, APA 7th, Chicago, MLA 9th, New York Times, Wikipedia |
| Maximum text | 100,000 characters per conversion |
| Line breaks | Preserved. Title and Sentence case apply per line. |
| Clean-up options | Trim line ends, collapse repeated spaces, remove line breaks |
| Counts returned | Words, characters, characters without spaces, sentences, lines, reading time |
| Reading speed used | 238 words per minute — the measured average for silent reading of English prose |
| Output | Copy to clipboard or download as a .txt file |
| Cost | Free, unlimited, no account |
Frequently asked questions
What is title case?
Title case capitalizes the significant words in a heading and leaves the minor ones lowercase. Every major style guide capitalizes nouns, pronouns, verbs, adjectives and adverbs, plus the first and last word of the title. They disagree about which short words stay lowercase, which is why one headline can be correctly capitalized two different ways.
What is the difference between AP and Chicago title case?
The split is prepositions. AP capitalizes words of four letters or more, so Walking Through the Woods keeps Through capitalized. Chicago lowercases prepositions regardless of length, giving Walking through the Woods. Both lowercase articles (a, an, the) and coordinating conjunctions (and, but, or, nor, for) unless one opens or closes the title.
Why does my title case converter capitalize 'in' and 'the'?
Because it is capitalizing the first letter of every word rather than applying a style guide. That naive pass gives you The Cat In The Hat instead of The Cat in the Hat, and it flattens acronyms and brand spellings on the way through. Correct title case needs a lowercase word list plus first-and-last-word handling.
Is 'is' capitalized in a title?
Yes. Is is a verb, and every major style guide capitalizes verbs in a title no matter how short they are, so This Is the Way is correct. Only articles, coordinating conjunctions and, depending on the guide, prepositions get lowercased, and even those are capitalized as the first or last word.
What is sentence case?
Sentence case capitalizes the first word of a sentence and any proper nouns, and leaves the rest lowercase, exactly like ordinary prose. It is standard for interface labels, reference lists in APA style and many publications' headlines. Converting to it properly means finding sentence boundaries and keeping names intact, not lowercasing the whole string.
How do I change uppercase to lowercase without retyping?
Paste the text into a case converter and select lowercase. That is faster than retyping and avoids introducing new typos in text that was already correct. If you need readable prose afterwards, run sentence case rather than lowercase, so the first word of each sentence and any names stay capitalized.
What is the difference between APA and MLA title case?
Prepositions and hyphens. APA capitalizes words of four letters or more, so Working With AI keeps With capitalized, while MLA lowercases prepositions of any length and gives Working with AI. Both capitalize the word after a hyphen, so both write Step-By-Step where AP and Chicago write Step-by-Step. Everything else about them agrees.
How do I convert text to camelCase or snake_case?
Paste the text and choose camelCase or snake_case; the converter re-splits the input into words first, so it does not matter whether you started with spaces, hyphens, underscores or existing camelCase. That means user first name, user-first-name and userFirstName all produce the same result, and the conversion works in either direction. CONSTANT_CASE, kebab-case, PascalCase, dot.case and path/case are the same operation with a different separator.
Does a case converter keep my line breaks?
Zyff's does, and it also treats each line separately. Title Case and Sentence case give every line its own opening capital, so a pasted column of names or product titles comes back capitalized line by line rather than only at the top. Switch on Remove line breaks if you want the opposite and need one paragraph out.
Why did my proper noun come back lowercase?
Because sentence case and lowercase cannot tell a name from an ordinary word. Nothing can, from the text alone — paris is a city and also a first name, and reed is a surname and also a plant. Type acronyms and brand names with their real capitals (NASA, iPhone, McDonald's) and Zyff leaves them exactly as written; anything typed entirely in lowercase needs the one or two fixes a human makes at the end.
Is my text stored anywhere?
No. Each conversion is self-contained: the text is sent to Zyff's server, converted in memory, returned, and the buffer holding it goes out of scope with the request. Nothing is written to a disk, a queue or a log, and because the tool needs no account there is no history to go back and empty.