Case Converter

Which words stay lowercase in Title Case?

Fifteen short words: a, an, the, and, but, or, for, nor, on, at, to, by, in, of, up. Every other word gets a capital, including is, with, from, as, over and into, which some style guides keep lowercase. The first word is always capitalised, and so is the first word after a colon, so "the lord of the rings: a guide to the film" becomes "The Lord of the Rings: A Guide to the Film". If your house style (AP, Chicago, APA) differs, adjust a few words by hand afterwards.

What happens to acronyms like NASA when I use Title Case or Sentence case?

They are flattened. Both modes lower-case the whole text before capitalising, so "NASA launched the ISS" becomes "Nasa Launched the Iss" in Title Case. The tool cannot tell an acronym from an ordinary word, so restore acronyms, names and the pronoun "I" by hand. Sentence case has the same limit: "john and i went home" becomes "John and i went home".

Does Sentence case capitalise every line?

No. It capitalises the first letter of the text and the first letter after a full stop, exclamation mark or question mark that is followed by a space or line break. A new line that follows no punctuation is not treated as a new sentence, so "first line" and "second line" on separate lines come out as "First line" and "second line". Add the missing full stops, or convert each line separately.

Can it split camelCase or PascalCase text into separate words?

No. The converters read word boundaries from spaces, underscores and hyphens only, and they lower-case everything first. "myVariableName" has no such boundary, so camelCase leaves it as "myvariablename", and snake_case also returns "myvariablename". To convert an existing identifier, first type it with spaces or underscores between the words.

What does it do with punctuation and accented letters in snake_case, kebab-case and CONSTANT_CASE?

It removes everything that is not a letter, a digit or the separator, then collapses repeated separators and trims them from both ends. "Page Title: SEO & Marketing!" becomes "page-title-seo-marketing" in kebab-case, with no double hyphen where the ampersand was. Accented and non-Latin letters are kept, so "Café au lait" becomes "café_au_lait". Check the result before using it as a URL slug, because browsers percent-encode non-ASCII characters in addresses.

How do camelCase and PascalCase treat punctuation and line breaks?

Only spaces, underscores and hyphens are removed. Other punctuation stays where it was, so "hello, big world" becomes "hello,BigWorld". Line breaks count as whitespace, so two lines are joined into one identifier: "line one" and "line two" give "lineOneLineTwo". Clean the text of commas, brackets and quotes before converting if you need a valid variable name.

Why can the result be longer than the original?

Upper-casing follows the Unicode rules of JavaScript, in which some letters expand. The German "ß" becomes "SS", so "dž ß straße" turns into "DŽ SS STRASSE" and grows from 10 to 12 characters. The opposite happens in the programming cases, where removed spaces and punctuation make the result shorter.

Is aLtErNaTiNg CaSe based on letters or on characters?

On characters. The pattern lower-upper-lower-upper counts every character, spaces and punctuation included, starting with a lowercase character at position 0. "Hello World" becomes "hElLo wOrLd": the space uses up a position, so the W lands on an even position and stays lower-case. Counting letters only would have given "hElLo WoRlD". It is a cosmetic effect, not a readability aid.