Changing the case of text is a two-second job by hand for a sentence and an unbearable one for a thousand rows of a spreadsheet. That is what this tool is for: paste text in, pick a case, get it back. But the naming conventions themselves are worth understanding, because using the wrong one in code or in a headline is a signal that gets noticed.
Case conventions are not cosmetic in programming. Most languages and frameworks have settled conventions, and following them is how other people read your code quickly.
The conventions and where they belong
| Case | Example | Used for |
|---|---|---|
| UPPERCASE | HELLO WORLD | Constants, acronyms, emphasis |
| lowercase | hello world | URLs, email addresses, tags |
| Title Case | Hello World | Headlines, book and article titles |
| Sentence case | Hello world | Body copy, UI labels, most modern headings |
| camelCase | helloWorld | JavaScript and Java variables |
| PascalCase | HelloWorld | Class names, React components |
| snake_case | hello_world | Python, Ruby, SQL columns |
| kebab-case | hello-world | URLs, CSS classes, file names |
Title case is not just capitalising everything
Proper title case capitalises the first and last words plus every principal word, while leaving short articles, conjunctions and prepositions in lowercase: "The Rise and Fall of the City" rather than "The Rise And Fall Of The City". Style guides disagree on the cutoff — AP lowercases prepositions of three letters or fewer, Chicago lowercases them regardless of length. Sentence case sidesteps the whole argument, which is one reason most modern interfaces have adopted it.
Practical uses
- Fixing text typed with caps lock on, without retyping it.
- Normalising imported data before comparing or deduplicating it.
- Converting a heading into a URL slug in kebab-case.
- Switching a variable name between conventions when porting code between languages.
- Toning down copy written in all caps, which reads as shouting and is measurably slower to read.
Why all caps is harder to read
Lowercase letters have distinctive ascenders and descenders that give words a recognisable outline, and fluent readers use that shape rather than reading letter by letter. Capitals are all the same height, so every word becomes a uniform rectangle and the shape cue disappears. Reading speed drops by roughly ten percent as a result. Use capitals for short labels where they add emphasis, and never for a paragraph.