Case Converter

About this tool

The mode menu lists sentence, upper, lower, title, slug, and alternating. Sentence case lowercases the whole text, then capitalizes a Latin letter a–z or a Ukrainian letter in а, я, і, ї, є, ґ when that letter is at the start of the text or immediately after a period, exclamation mark, or question mark and the whitespace that follows it. HELLO WORLD. second line becomes Hello world. Second line. A comma does not start a new sentence. Title case uses the same lowercase pass, then capitalizes one of those letters at the start or after whitespace. hello world becomes Hello World. hello-world becomes Hello-world, because the hyphen is not whitespace and the w is not recapitalized.

Upper and lower call the ordinary JavaScript case conversion, so they cover the characters the language maps, not only the Latin and Ukrainian ranges the sentence and title patterns know. An accented letter that sentence case leaves alone can still change under upper or lower. Slug lowercases, trims, deletes every character outside ASCII letters, digits, spaces, hyphens, and the same Ukrainian range, turns runs of spaces into one hyphen, collapses repeated hyphens, and trims hyphens from the ends. Hello, World! becomes hello-world. The comma and the exclamation mark are deleted rather than turned into hyphens. An underscore is deleted too, because it is not in the kept set, so hello_world becomes helloworld rather than hello-world.

Alternating case does not lowercase the string first. It walks the original characters by index. An even index, starting at 0, is lowercased, and an odd index is uppercased. Hello becomes hElLo. The h is index 0. Spaces and punctuation occupy an index too, so they shift the phase of the letters after them. The mode is a visual effect. It is not a capitalization style. A preset page sets the mode menu and still waits for you to run the conversion. An empty input returns before a result is written, so a previous output stays on the screen. A mode the menu does not list would copy the text through, and the menu does not offer that. Nothing is stored or uploaded. The slug is a cleanup of the characters above. It does not transliterate é to e, and it does not translate words. Sentence case will not capitalize an é at the start of école, because é is outside the letter class the pattern recognizes. Use upper or lower when you need the broader Unicode mapping.

Example. Slug turns Hello, World! into hello-world. Sentence case turns HELLO WORLD. second line into Hello world. Second line. Alternating case turns Hello into hElLo. Title case turns hello world into Hello World.

Limit. Sentence and title case only capitalize a–z and а-яіїєґ. Slug deletes other letters instead of transliterating them. An empty input leaves the previous output in place.