Case converter guide
How to use a case converter for sentences, titles and code
In short
Paste your text and pick a style: Sentence case, Title Case, Capitalize Every Word, lowercase, UPPERCASE or one of the developer formats like camelCase and snake_case. The converted text appears straight away, with a list of every word that changed. Acronyms such as NASA, web addresses and any names you add to the protected list keep their exact spelling. Nothing changes in your original until you press Apply to editor.
- Text styles
- Sentence, Title, UPPER, lower and more
- Developer styles
- camelCase, snake_case, kebab-case
- Protected
- Acronyms, links, your own terms
- Where your text goes
- Nowhere. It stays in your browser
How to convert text to another case
Paste your text into the editor. The original stays untouched while you try different styles.
Choose a style from the buttons, or open More formats for alternating case and the developer formats.
For titles, pick a Title capitalization rule. Add any names or brands that must keep an unusual spelling, like iPhone or eBay, to “Keep this exact spelling”.
Check the Change report, then copy the result, download it, or press Apply to editor. Restore original undoes it.
Sentence case, title case, uppercase and lowercase explained
| Style | Example | Use it for |
|---|---|---|
| Sentence case | A guide to clear writing | Body text, headings in many style guides, fixing ALL CAPS |
| Title Case | A Guide to Clear Writing | Book, article and film titles; headlines |
| Capitalize Every Word | A Guide To Clear Writing | Names, product listings, labels |
| Capitalize Each Line | One capital at the start of every line | Lists and one-line headings |
| lowercase | a guide to clear writing | Tags, usernames, consistent data |
| UPPERCASE | A GUIDE TO CLEAR WRITING | Short labels and warnings |
| tOGGLE cASE | hELLO becomes Hello | Flipping text typed with Caps Lock on by accident |
Sentence case is the one that fixes text written in ALL CAPS. It lowercases everything, then capitalizes the first word of each sentence and the start of each new paragraph. Acronyms stay in capitals, so “THE NASA REPORT IS LATE.” becomes “The NASA report is late.”
Title case rules: which words are not capitalized?
In title case, the important words get a capital and short function words (articles, some conjunctions and short prepositions) usually don't. The first and last word are always capitalized. Where the style guides disagree is how short a “short” word is.
| Style guide | Keeps lowercase (unless first or last) | So these are capitalized |
|---|---|---|
| AP | Articles, conjunctions and prepositions of 3 letters or fewer | With, From, Into |
| APA 7 | Articles, conjunctions and prepositions of 3 letters or fewer | With, From, and short verbs like Is |
| Chicago (18th edition) | Articles; and, but, for, or, nor; to; prepositions of 4 letters or fewer | Prepositions of 5 or more letters, such as Between |
| MLA 9 | Articles, all prepositions, coordinating conjunctions, to | Subordinating conjunctions such as Because |
The converter offers four rules. “APA-style threshold” and “AP-style length rule” both keep short articles, conjunctions and prepositions of three letters or fewer in lowercase. “Chicago-style minor words” keeps a fixed list lowercase: a, an, the, and, but, for, nor, or, so, yet, as, at, by, from, in, of, on, per, to, via and with. “General major words” is the default: it keeps a, an, and, as, at, but, by, for, from, if, in, nor, of, on, or, per, so, the, to, up, via, vs and yet lowercase at any length. If your style guide lowercases a word that isn't on the list, such as “amid” or “versus”, add it under “Additional lowercase title words”.
Keep acronyms, brand names and links as written
A plain conversion turns “NASA” into “Nasa” and “iPhone” into “Iphone”. This converter protects three kinds of text by default: words already written in capitals (NASA, HTML, PDF), web addresses and email addresses. You can add your own terms, separated by commas or new lines, and they're matched whatever their case and put back with your spelling.
When three-quarters or more of the text is in capitals, every word looks like an acronym, so the converter only keeps a built-in list (such as API, FAQ, NASA, SEO, UK and USA) plus words with digits or symbols. Names of people and places can't be detected reliably, so give the result a read before you use it.
camelCase, PascalCase, snake_case and kebab-case
| Format | Result | Common use |
|---|---|---|
| camelCase | clearWritingGuide | JavaScript variables and JSON keys |
| PascalCase | ClearWritingGuide | Class and component names |
| snake_case | clear_writing_guide | Python, database columns |
| kebab-case | clear-writing-guide | URLs, CSS classes, file names |
| CONSTANT_CASE | CLEAR_WRITING_GUIDE | Constants and environment variables |
These formats turn your text into a single identifier, so spaces and punctuation are removed on purpose. Existing camelCase is split at the capital letters first, so userName becomes user_name.
Uppercase and lowercase in other languages
Changing case isn't the same in every language. In Turkish, lowercase “i” becomes a dotted capital “İ”, and capital “I” becomes a dotless “ı”. In German, “ß” becomes “SS” in capitals, so the word gets longer. Pick the language under “Language-aware casing” (English, Turkish, Azerbaijani, German, French, Spanish, Portuguese, Dutch or Polish) and the converter follows its rules.
Common questions
What is sentence case?
Sentence case capitalizes only the first word of each sentence and proper nouns, like a normal sentence. “How to write a good title” is in sentence case.
What's the difference between sentence case and title case?
Sentence case capitalizes the first word only. Title case capitalizes every important word and leaves short words like “and”, “of” and “the” in lowercase unless they come first or last.
Does the title case converter follow APA, AP or Chicago style?
Yes. Choose Title Case, then pick a Title capitalization rule: the APA and AP options keep short words of three letters or fewer in lowercase, the Chicago option keeps its fixed list of minor words lowercase, and the default keeps common short words lowercase. You can add your own lowercase words too.
Which words should not be capitalized in a title?
Usually articles (a, an, the), coordinating conjunctions (and, but, or) and short prepositions (in, of, on, to), unless they're the first or last word. How short “short” is depends on the style guide.
Is “with” capitalized in a title?
In AP and APA style, yes, because it has four letters. In Chicago and MLA style, no, because it's a short preposition.
How do I fix text typed in all caps?
Paste it in and choose Sentence case. Everything is lowercased and each sentence gets a capital first letter. Acronyms from a built-in list, such as NASA or USA, stay in capitals.
How do I capitalize the first letter of each word?
Choose Capitalize Every Word. Unlike Title Case, it capitalizes every word, including “and”, “of” and “the”.
Will it change acronyms like NASA or brand names like iPhone?
Acronyms written in capitals are kept by default. Add brand names with unusual capitals, such as iPhone or eBay, to “Keep this exact spelling” and they'll always come out as you typed them.
How do I convert text to camelCase or snake_case?
Open More formats and choose camelCase, PascalCase, snake_case, kebab-case or CONSTANT_CASE. Spaces and punctuation are removed to make one identifier.
How do I change case in Microsoft Word?
Select the text and press Shift+F3 to cycle between lowercase, UPPERCASE and capitalizing each word. Word doesn't apply style-guide title case, which is where a case converter helps.
Is my text uploaded?
No. The conversion runs in your browser, and your original text isn't changed until you choose Apply to editor.
Sources
- Capitalization of titles (Chicago 18th edition Q&A)The Chicago Manual of Style Online
- APA headings and title caseScribbr
- Capitalizing titles in MLAScribbr
- Title capitalization rulesTitle Case Converter
- String.prototype.toLocaleUpperCase()MDN Web Docs