How to change text case without retyping it
UPPERCASE, lowercase, Title Case, Sentence case — what each one actually means, and the gotchas when your text has names, acronyms, or non-Latin scripts.
You pasted a heading, only to realise it's all caps. Or you typed three paragraphs with caps lock on. Retyping is a punishment for a problem the browser can solve in one click.
The four cases that matter
UPPERCASE turns every letter into its capital form. Browsers use the Unicode toUpperCase() method, which knows about German ß → SS, Turkish i → İ, and dozens of script-specific quirks.
lowercase is the inverse. Same Unicode awareness.
Title Case capitalises the first letter of every word. The word boundary is whitespace — so "don't" becomes "Don't" (the apostrophe is treated as inside a word), but "well-known" becomes "Well-Known" (the hyphen splits words).
Sentence case capitalises the first letter of each sentence. Sentence boundaries are detected by ., ?, and ! followed by whitespace.
The Case Converter gives you all four with one click.
The gotchas
Acronyms get lowercased. "NASA was founded" → "Nasa Was Founded" in title case. The tool doesn't know that NASA should stay uppercase. After conversion, scan for acronyms and fix them by hand if you care.
Names with internal capitals (camelCase, McDonald, iPhone) get flattened. "iPhone" becomes "iphone" in lowercase, "IPHONE" in upper, "Iphone" in title. There is no general rule that recovers the original — your editor's autocorrect doesn't help here either.
Non-Latin scripts mostly work. Cyrillic, Greek, Armenian — they all have upper/lower forms that the Unicode tables handle. Scripts without case (Arabic, Chinese, Japanese, Korean, Devanagari) are unchanged by upper/lower; title case capitalises only the Latin words inside them.
A small workflow
- Paste the text into the input.
- Click the case you want.
- Copy the result.
- Scan for acronyms and proper nouns that need fixing.
That last step is the one most "case converters" pretend doesn't exist. The brute-force pass takes two seconds; the cleanup pass takes the time it takes. There's no magic.
When you need something more specialized
- Programmer case (camelCase, snake_case, kebab-case)? Use the Slug Generator — it has more options for separator and casing rules.
- A specific subset (only words after colons, only acronyms)? You're past the point of a generic tool. A 5-line regex in your editor is faster.
For "make this title look right" or "fix this all-caps email," one click here is the whole answer.