Paste your text, pick a case, copy the result. Convert to UPPERCASE, lowercase, Title Case, Sentence case, camelCase, snake_case and more — instantly, in your browser.
Paste your text into the box above, choose a case, and the text is converted in place — there is no convert button to hunt for and no page reload. Copy the result with one click, or download it as a .txt file. If a conversion was not what you wanted, Undo restores your original text, which matters because case conversion is lossy: once a sentence is lowercased, the tool cannot know which words were proper nouns. Everything runs in JavaScript inside your own tab, so there is no upload, no length limit, and the page keeps working offline once it has loaded.
A case converter changes the capitalization of text without you retyping it. Writers use one to fix a headline typed with Caps Lock on, or to switch a heading between Title Case and Sentence case. Developers use one to move a variable name between camelCase, snake_case and kebab-case. Anyone who has pasted a column of ALL CAPS names out of a spreadsheet has needed one.
The two most common jobs are the simplest. To convert uppercase to lowercase — undoing an accidental Caps Lock, or toning down text that was typed in all caps — paste it and press lowercase. To go the other way and convert lowercase to uppercase, press UPPER CASE. Capital letters, caps, all caps, upper case and uppercase all describe the same thing, so whichever phrase you searched for, these two buttons are what you came for. One caution on the downward direction: lowercase strips every capital, including proper nouns and the pronoun "I", so for a full paragraph Sentence case usually gives a better result than plain lowercase.
Each style below is a button in the tool. The same sentence is shown converted so you can see the difference at a glance.
| Style | "the quick brown fox jumps over the lazy dog" becomes |
|---|---|
| UPPER CASE | THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG |
| lowercase | the quick brown fox jumps over the lazy dog |
| Sentence case | The quick brown fox jumps over the lazy dog |
| Capitalize Each Word | The Quick Brown Fox Jumps Over The Lazy Dog |
| Title Case (AP) | The Quick Brown Fox Jumps Over the Lazy Dog |
| camelCase | theQuickBrownFoxJumpsOverTheLazyDog |
| PascalCase | TheQuickBrownFoxJumpsOverTheLazyDog |
| snake_case | the_quick_brown_fox_jumps_over_the_lazy_dog |
| CONSTANT_CASE | THE_QUICK_BROWN_FOX_JUMPS_OVER_THE_LAZY_DOG |
| kebab-case | the-quick-brown-fox-jumps-over-the-lazy-dog |
Sentence case capitalizes only the first letter of each sentence, exactly as you would write ordinary prose. This tool detects sentence boundaries rather than blindly splitting on every full stop, so abbreviations such as "Dr.", "e.g." and "U.S." do not start a false new sentence. Capitalize Each Word — also called Capital Case or Proper Case — capitalizes every word without exception, which is what spreadsheet functions like PROPER do.
Title Case is not simply capitalizing every word. Short function words — articles, conjunctions and prepositions — stay lowercase unless they are the first or last word of the title, or they follow a colon. That is why "The Lord of the Rings" keeps "of" and the second "the" in lowercase. Style guides disagree about where to draw the line, so the tool offers four: pick AP, APA, MLA or Chicago from the selector and the conversion follows that guide's word list.
"Is" is always capitalized: it is a verb, and only articles, conjunctions and prepositions are lowercased — a rule people get wrong because "is" is such a short word. "The", "a" and "an" are articles, so they stay lowercase unless they open or close the title. "And", "but", "or" and "nor" are coordinating conjunctions and stay lowercase. "To", "of", "in" and "at" are short prepositions and stay lowercase in every guide. "With" is where guides split: AP and APA capitalize prepositions of four letters or more, so they write "With", while MLA and Chicago lowercase every preposition regardless of length.
Use Title Case for published titles: headlines, book and article titles, and anything following AP, APA, MLA or Chicago. Use Sentence case for interface copy, product documentation, error messages and most modern web writing — it is easier to read and it is what most contemporary design systems specify.
You do not always need a separate tool. In Excel and Google Sheets, use a formula in a helper column: <code>=UPPER(A1)
Naming conventions are how code stays readable, and each ecosystem picked a different one. camelCase starts lowercase and capitalizes each following word (<code>userFirstName
The converter reads word boundaries from both delimiters and existing capitals, so any of these styles converts cleanly into any other: paste <code>myXMLParserV2
If you need the conversion inside a program rather than on a page, every language has it built in. In JavaScript, <code>text.toUpperCase()
Paste the text into the box above and press the lowercase button. For a whole paragraph, consider Sentence case instead: plain lowercase removes every capital including proper nouns and the pronoun "I", while Sentence case puts the capital back at the start of each sentence.
In Microsoft Word and Excel, select the text and press Shift+F3 to cycle through lowercase, Capitalize Each Word and UPPER CASE. Google Docs uses Format > Text > Capitalization. Both were checked against Microsoft's and Google's own documentation.
Yes, always. Only articles, coordinating conjunctions and prepositions are lowercased in Title Case. "Is" is a verb, so it is capitalized in every style guide — it just looks like it should be lowercase because it is short.
Title Case capitalizes the important words and leaves short function words lowercase, and it is used for headlines and published titles. Sentence case capitalizes only the first word of each sentence, like ordinary prose, and is standard for interface copy and documentation.
Yes. The "Keep these words as-is" field holds a list of words that every conversion leaves untouched, pre-filled with common acronyms and product names. Add your own product names, ticker symbols or internal abbreviations to the list and they will be preserved too.
Yes. Tick "Convert each line separately" and every line is treated as its own piece of text, which is what you want for a column copied out of Excel or Google Sheets, a list of filenames, or CSV fields. There is no row limit.
Yes. The conversion runs in JavaScript in your own browser tab. Nothing is uploaded, stored or logged, and the page keeps working with your network disconnected once it has loaded — so it is safe for client lists, unpublished copy and material under NDA.
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