--- title: "Case Converter - UPPERCASE, lowercase, Title Case | CanDoYa" description: "Free online case converter. Convert text to UPPERCASE, lowercase, Title Case, Sentence case, Capitalize Words, aLtErNaTiNg or iNvErSe in your browser." url: https://candoya.com/tools/case-converter/ locale: en type: browser-tool --- # Case Converter Category: Text & Writing ## What is a case converter? A case converter changes the letter case of text without retyping it. This tool runs seven conversions in your browser: UPPERCASE, lowercase, Title Case (AP/Chicago style), Sentence case, Capitalize Each Word, aLtErNaTiNg cAsE and iNvErSe CaSe. Paste a sentence, a heading or a whole article, pick a mode, and copy the result. Conversion runs as you type and stays on your device - the text is never uploaded, which makes it safe for unpublished drafts, internal docs and AI prompts. **Title Case** follows AP/Chicago: minor words like *a, an, the, and, of, in, on, to* stay lowercase unless they are the first or last word. **Sentence case** lowercases everything and re-capitalizes the start of each sentence, preserving the pronoun "I" and its contractions. Acronyms in all-caps (NASA, HTML) are left intact in Title and Capitalize modes so you don't have to retype them. ## How to use it 1. **Paste your text** - Type or paste the text you want to convert into the left box. The tool works on a word, a sentence, or thousands of lines at once. 2. **Pick a case** - Tap UPPERCASE, lowercase, Title Case, Sentence case, Capitalize Words, aLtErNaTiNg or iNvErSe. The converted text appears live on the right. 3. **Copy or chain** - Press Copy to put the result on your clipboard, or Use as input to pipe it back into the input box and apply another conversion (lowercase first, then Title Case). ## Who it's for - **Writers and editors** fixing a headline pasted in shouty caps, or normalising a quote that arrived in `SENTENCE CASE`. - **Students and bloggers** applying Title Case to article titles and chapter headings without memorising the AP rule list. - **Developers** cleaning up CSV columns, log lines or label copy before it ships - paste a column, lowercase it, copy back. - **AI prompters and content teams** normalising LLM output that mixes cases, or generating playful aLtErNaTiNg text for social posts. ## Expert note Most online case converters "Title Case" every word - including *of*, *the* and *and* - which is why so much web copy reads like a 1990s yearbook. This tool follows the AP/Chicago convention: the first and last word of each line are always capitalised, plus every word that isn't in a small fixed list of articles, conjunctions and short prepositions. Tokens that are already all-uppercase (`NASA`, `HTML`, `IBM`) are preserved instead of being mangled to `Nasa`, and hyphenated compounds like `self-driving` have each segment capitalised. ## Frequently asked questions ### Is this case converter free? Yes - 100% free, no sign-up and no character limits. Conversion happens in your browser, so it's also fast on very large pastes. ### Is my text uploaded anywhere? No. Everything runs locally in your browser and never reaches a server, so it's safe for confidential drafts, contracts and AI prompts. ### What is the difference between Title Case and Capitalize Each Word? Title Case follows AP/Chicago style: short words like a, an, the, and, of, in, on, to stay lowercase unless they're the first or last word. Capitalize Each Word is the naive form - it capitalises every single word, even the small ones. Pick Title Case for headlines and book titles, Capitalize for slugs or labels. ### How does Sentence case decide where a sentence ends? It lowercases the whole text, then re-capitalises the first letter after a period, exclamation mark or question mark that is followed by whitespace (so abbreviations like `i.e.`, `e.g.` and `U.S.A.` stay intact internally - the periods between letters don't reset capitalisation). The pronoun "I" and contractions (I'm, I'll, I've, I'd) are preserved capitalised. Mid-text abbreviations followed by a space, like "i.e. ", are still treated as sentence breaks - there's no reliable way to disambiguate without a dictionary. ### Does it handle accents, German ß, Greek, Cyrillic? Yes. UPPERCASE and lowercase use the browser's Unicode case mapping, so é -> É, ñ -> Ñ, ß -> SS and я -> Я all work. CJK scripts, Arabic and Hebrew have no concept of letter case, so they pass through unchanged. ### Will it break my acronyms like NASA or HTML? No. Title Case and Capitalize Each Word detect tokens that are entirely uppercase (two letters or more) and leave them as-is, so a paste containing NASA, HTML or IBM stays exactly that way. ### What is aLtErNaTiNg case for? It's the mocking SpongeBob meme style - aLtErNaTiNg lowercase and uppercase letter by letter. Useful for social posts and chat humour. Non-letter characters (spaces, punctuation) pass through and don't break the rhythm. ### Can I undo or chain conversions? Yes. The input box is never modified - your original text stays put. Press Use as input to push the current result back into the input box, then apply another mode (for example, lowercase first, then Title Case). ## Related tools - [Word Counter](https://candoya.com/tools/word-counter/) - [Character Counter](https://candoya.com/tools/character-counter/) - [Sentence Counter](https://candoya.com/tools/sentence-counter/) - [Readability Score Checker](https://candoya.com/tools/readability-score/) - [Reading Time Calculator](https://candoya.com/tools/reading-time-estimator/) --- *Markdown edition of , published for AI agents and other automated readers. Index of key pages: .*