What This Tool Does
Paste text once and every case appears at the same time: UPPERCASE, lowercase, Title Case, Sentence case, Capitalize Each Word and aLtErNaTiNg for prose; camelCase, PascalCase, snake_case, CONSTANT_CASE, kebab-case and dot.case for identifiers; plus No diacritics and URL slug for Vietnamese.
Nothing is overwritten. Your text stays exactly where you typed it, and each card has its own Copy button, so comparing two cases before choosing takes no clicks at all.
Load the sample text to see all fourteen cases at once: the small words stay lowercase inside Title Case, and XMLHttpRequest splits into its parts for the identifier cases. Paste in Vietnamese text instead to see the identifier cases fold its tone marks.
How to Use It
Type directly into the editor, paste from anywhere, or load a .txt, .md, .docx or .pdf file. Set the language to Auto-detect and the tool works out whether it is looking at Latin, Vietnamese or CJK text — or override it if you are converting a name or a fragment too short to detect.
Copy takes the case you want. Copy always converts the whole document, even when the cards are showing a shortened preview.
Need the full breakdown instead of a different case — word count, reading time, keyword density? The Word Counter runs the same text through all of that.
Working with a list rather than prose? Line Tools sorts, deduplicates and joins lines in one pass.
The Fourteen Cases
The prose cases keep your punctuation, line breaks and spacing exactly as they were: only the letters change. The identifier cases throw punctuation away by definition, since a variable name cannot contain it.
Capitalize Each Word and Title Case are different on purpose. Capitalize Each Word capitalizes every word with no exceptions. Title Case applies real typographic rules, so small words stay lowercase in the middle of a title.
Why Vietnamese Is Handled Differently
Vietnamese writes each syllable separately and marks tone with diacritics, which matters twice here.
For Title Case, there is no Vietnamese convention to follow. Applying the English small-word list to Vietnamese produces nonsense, because an, in, so and to are all real Vietnamese syllables — ky thuat an ninh mang would come back as Ky Thuat an Ninh Mang, with a real word left lowercase in the middle of a title. This tool capitalizes every syllable instead, and tells you on the card that the result is mechanical rather than orthographically correct.
For identifiers, the marks have to go, because a variable name is expected to be ASCII. The fold separates each mark from its base letter and removes only the mark, so học sinh giỏi becomes hoc sinh gioi and not hc sinh gii. The letter đ is handled separately, because it is a distinct letter rather than a decorated d.
Identifiers and Slugs Are Not the Same Thing
kebab-case and a URL slug both produce lowercase words joined by hyphens, and they answer different questions. Kebab-case is a naming convention: it keeps whatever letters survive folding, including scripts that have nothing to fold. A slug has to survive being pasted into a URL, so it is restricted to a-z, 0-9 and hyphens.
For English and Vietnamese input the two agree. For Chinese, Japanese or Korean they diverge sharply — and the slug card says so rather than handing back an empty box with no explanation.