Case Converter

How to use the case converter

1. Paste or type your textAnything from a single heading to several pages works. The word and character totals under the box update as you type.
2. Pick a caseEach button converts the whole box in place. Try a few: every click starts again from the text you pasted, so switching from camelCase back to Title Case loses nothing.
3. Decide about acronymsWith Keep acronyms on, words written entirely in capitals, like PDF or UNESCO, survive Sentence and Title case. Turn it off when the capitals are just emphasis you want gone.
4. Copy the resultCopy puts the converted text on your clipboard and the button briefly says Copied. Undo takes you back one step to the text before conversion.

Every case, what it looks like and where it is used

The same phrase, parse HTTP response, run through each button, and the places where each style is the normal choice.

How Title Case is decided

No single title case rule exists; publishers disagree mainly about prepositions. This converter follows a length rule that is easy to predict: short function words stay lowercase, everything else gets a capital. In practice that means:

• Always capitalized: the first word, the last word, and the first word after a colon, so Star Wars: A New Hope and What Are You Looking For.
• Always lowercase in the middle: the articles a, an and the; the conjunctions and, but, or, nor, for, so and yet; and prepositions of three letters or fewer, such as of, in, on, at, by and to.
• Hyphenated words: each part is judged on its own, which turns state-of-the-art into State-of-the-Art and well-known into Well-Known.
• Left alone: words that already have a capital after the first letter, like McKenzie or DeLuca, and all-capital acronyms while Keep acronyms is on.

Up, off and out are deliberately not on the lowercase list. In titles they are usually part of a phrasal verb, as in Setting Up Your Router or How to Log Out, and style guides generally capitalize a word used that way.

Where the big style guides differ

The output of this tool matches AP and APA for prepositions. For Chicago, lowercase four-letter prepositions such as with, from, into and over by hand; for MLA, lowercase every preposition in the middle of the title. Earlier editions of the Chicago manual, up to the 17th, lowercased prepositions of any length, so older house styles may still expect that.

The title case rules guide goes through each word class with worked headlines, including the tricky ones: subordinating conjunctions, the word to, and phrasal verbs.

Code naming styles in practice

Programmers join several words into one identifier because spaces are not allowed in names. Which joiner you use is mostly a matter of the language community you are writing for, and style checkers in many projects enforce it.

• Python uses snake_case for functions and variables, PascalCase for classes and CONSTANT_CASE for module-level constants, as set out in its official style guide.
• JavaScript and Java use camelCase for variables and methods and PascalCase for classes; constants are often in CONSTANT_CASE.
• Go uses the capital letter itself as a rule: a name that starts with a capital is visible outside its package, so the choice between camelCase and PascalCase changes what the code exposes.
• Web addresses and style sheets use kebab-case. Search engines treat hyphens in a URL as word separators, which is one reason title-case-rules is preferred over title_case_rules in page addresses.
• Shell and server settings use CONSTANT_CASE for environment variables, such as a variable that holds a port number or a log level.

When converting to a code style, each line of your text becomes one identifier. The converter splits words at spaces, punctuation, underscores and hyphens, and also at the point where a lowercase letter meets a capital, so getUserID becomes get, user and id. A run of capitals followed by a capitalized word is split before the last capital, which turns XMLHttpRequest into xml, http and request. Digits stay attached to the word they touch: utf8 decoder becomes utf8Decoder, not utf8_decoder with a separate 8.

Pitfalls to check after converting

Acronyms and initialisms

A converter can only guess that NASA is an acronym because it is written in capitals. An acronym typed in lowercase, such as nasa, stays lowercase in Sentence case, and a short shouted word such as OK or NO is kept in capitals when Keep acronyms is on. In code styles acronyms are always treated as normal words, which gives parseHttpResponse rather than parseHTTPResponse; several popular style guides for code recommend exactly that, because it keeps word boundaries visible.

Proper nouns

Sentence case lowercases everything that does not start a sentence, including names of people, places, months and weekdays. We met in paris on monday is what you get from WE MET IN PARIS ON MONDAY, and only a person knows to restore the capitals. The pronoun I is the one exception the converter handles for you, along with its contractions such as I'm and I'll.

Names with unusual capitals

Title Case capitalizes only the first letter of a word, so o'neill becomes O'neill and macdonald becomes Macdonald. If a name is already written correctly, with a capital in the middle, the converter keeps it; if it arrives in lowercase, fix it by hand.

Letters outside English

Case rules follow the Unicode standard, which is right for most languages but not all. German ß has no single capital form in that mapping, so straße in UPPERCASE becomes STRASSE, one letter longer. Turkish uses a dotted and a dotless i, and the general mapping turns the capital I into an ordinary dotted i, which is wrong in Turkish text. Greek works well, including the special final form of sigma at the end of a word. Many programming languages accept accented letters in identifiers, but databases and older tools may not, so check before using é or ñ in a snake_case column name.