Case converter: change text to upper, lower or title case

What each case does

UPPERCASE turns every letter into a capital, useful for headings and labels. lowercase does the opposite, which helps when text was typed with Caps Lock on. Title Case gives every word a capital first letter, as in many headlines and book titles. Sentence case keeps only the first letter of each sentence and each line in capitals, and turns a lone i into I.

The last three are for programmers and file names. camelCase joins words and capitalises each one after the first, like invoiceTotal. snake_case joins words with underscores, like invoice_total. kebab-case uses hyphens, like invoice-total, which also works well for web page addresses. Existing camelCase is split into words first, so userID becomes user_id.

Hindi and other scripts

Devanagari has no capital and small letters, so Hindi words stay exactly as they are while English words around them change. In snake_case and kebab-case, Hindi words keep their matras and are joined with an underscore or hyphen. Accented Latin letters and scripts such as Cyrillic and Greek, which do have cases, are converted correctly.

Tips and limits

Title Case capitalises every word, including short ones like a, of and the, and it lowers the rest of each word, so acronyms such as GST become Gst. Read the result once and fix names and acronyms by hand. Sentence case cannot recognise proper nouns, so names inside a sentence need a quick check too.