How to change letter case
- Paste your text into the box. It can be a sentence, a paragraph or a list with one item per line.
- Press one of the buttons. The result appears below and keeps updating as you edit the original.
- Copy the result, or press Use result as input to apply another conversion on top.
The For writing buttons change only letter case, keeping every space and punctuation mark. The For code buttons split each line into words and join them again in the chosen naming style, which removes spaces and punctuation. Each line is converted separately, so a column of field names pasted from a spreadsheet comes back as a column.
The rules each style follows
Title Case
Title Case capitalises the important words and leaves short function words in lower case. This tool follows the rule in the Chicago Manual of Style, which most English-language publishers use: articles (a, an, the), coordinating conjunctions (and, but, or, nor, for, so, yet) and short prepositions (as, at, by, in, of, off, on, per, to, up, via) stay lower case — unless they are the first or last word, which is always capitalised. Hyphenated compounds get a capital on each part, as in Well-Known. AP style differs slightly (it capitalises prepositions of four letters or more); if you are writing to a specific style guide, check the handful of borderline words.
Sentence case
Sentence case lowers everything and then capitalises the first letter of the text and of each sentence, found after a full stop, question mark or exclamation mark followed by a space. It cannot know which words are proper nouns, so names like London or JavaScript come back lower case and need fixing by hand.
Naming styles for code
Identifiers are first split into words. Spaces, underscores, hyphens and other punctuation separate words, and so do changes of case: fooBar becomes foo and Bar, and a run of capitals followed by a capitalised word is split before the last capital, so XMLHttpRequest becomes XML, Http and Request. Digits stay attached to the word they follow. The words are then joined:
| Style | Joined as | Common in |
|---|---|---|
| camelCase | first word lower, others capitalised | JavaScript and Java variables, JSON keys |
| PascalCase | every word capitalised | class and type names, C# members |
| snake_case | lower case, underscores | Python, Ruby, SQL columns |
| kebab-case | lower case, hyphens | URLs, CSS classes, file names |
| CONSTANT_CASE | upper case, underscores | constants, environment variables |
Other alphabets
Upper and lower case follow Unicode rules, so accented letters convert correctly and the German ß becomes SS in upper case. Chinese, Japanese and other scripts without letter case pass through unchanged.
Examples
| Input | Style | Result |
|---|---|---|
the lord of the rings | Title Case | The Lord of the Rings |
what are you looking at | Title Case | What Are You Looking At (last word capitalised) |
HELLO. WORLD! how ARE you? fine | Sentence case | Hello. World! How are you? Fine |
hello world foo | camelCase | helloWorldFoo |
hello world foo | CONSTANT_CASE | HELLO_WORLD_FOO |
XMLHttpRequest | snake_case | xml_http_request |
Straße | UPPERCASE | STRASSE |
Renaming a batch of database columns: paste Customer ID, Order Date and Total Amount on three lines and press snake_case to get customer_id, order_date and total_amount.
Limits
- Proper nouns and acronyms. Sentence case and lowercase cannot tell that NASA or Paris should keep their capitals. Title Case capitalises every major word, so iPhone becomes Iphone.
- Style guides differ. Chicago, APA, AP and MLA disagree on a few words in Title Case — mostly longer prepositions such as "with" and "about". Check the guide you are writing for.
- Language rules. Title Case rules are for English. In French, Spanish and German, titles usually capitalise only the first word and proper nouns (plus all nouns in German), which Sentence case gets closer to.
- Locale-specific letters. The Turkish dotted and dotless i follow general Unicode rules rather than Turkish ones.
Frequently asked questions
How do I undo Caps Lock text?
Paste it and press Sentence case. Everything becomes lower case except the first letter of each sentence; then fix any names by hand.
Which words stay lower case in Title Case?
Articles, coordinating conjunctions and short prepositions, following the Chicago Manual of Style — unless they are the first or last word.
What is the difference between camelCase and PascalCase?
camelCase starts with a lower-case letter (userName); PascalCase starts with a capital (UserName). Both capitalise the start of every following word.
Can I convert many lines at once?
Yes. Each line is converted on its own and line breaks are kept.
Is my text sent anywhere?
No. The conversion happens in your browser and nothing is stored.