Text Case Converter

How to use

Type or paste your text into the input box and all 10 case formats appear instantly below. Click any "Copy" button to copy that specific result to your clipboard. The tool supports up to 10,000 characters.

Common uses include renaming variables and functions when switching programming languages, formatting English titles with proper Title Case, or generating social media text in all caps. Japanese, Chinese, emoji, and full-width characters are preserved unchanged — only Latin letters (A–Z, a–z) are affected by the conversion.

Conversion rules explained

UPPERCASE / lowercase: Every Latin letter in the text is shifted to upper or lower case. Symbols, digits, spaces, and non-Latin characters are left as-is.

Title Case: The first letter of each word is capitalized. However, certain short function words — the, a, an, of, in, on, at, for, but, nor, or, so, yet — are kept lowercase when they appear in the middle of the text. The first and last word are always capitalized regardless of this rule.

Sentence case: The entire text is first lowercased, then the very first letter and any letter that follows a period (.), exclamation mark (!), or question mark (?) followed by a space is capitalized. Abbreviations like Dr. or Mr. may be misidentified as sentence boundaries — a known limitation of this simplified implementation.

camelCase / PascalCase: The text is first split into tokens (the smallest meaningful word units) by detecting spaces, hyphens, underscores, dots, slashes, and camelCase / PascalCase boundaries inside words. camelCase keeps the first token lowercase and capitalizes all subsequent tokens. PascalCase capitalizes every token.

snake_case / kebab-case / CONSTANT_CASE / dot.case: The same token-splitting algorithm is applied, and the tokens are joined with underscores, hyphens, underscores (all caps), or dots respectively.

Unique angle A — Naming conventions by programming language and why they matter: Each language community has its own preferred conventions, and these conventions are not mere style preferences — they are often enforced by language specifications and toolchains. snake_case is the standard for Python variables and functions (PEP 8), Ruby, and database column names. camelCase is typical for JavaScript and Java variables and method names. PascalCase is used for React component names, class names across languages, and C# methods. kebab-case appears in HTML attributes, CSS classes, npm package names, and URL slugs. CONSTANT_CASE is the convention for constants and environment variables across most languages. dot.case is used for namespaces and config keys (e.g. app.config.value). A concrete example of why this matters beyond readability: kebab-case cannot be used for JavaScript variable names because the hyphen (-) is the subtraction operator. Writing my-var would be parsed as my minus var, causing a syntax error. Linters and formatters can catch these violations mechanically, which means adopting the right case style is a toolchain compatibility issue, not just an aesthetic choice.

Unique angle B — Title Case small-word rules and common misconceptions: English headline capitalization keeps short function words (articles, short prepositions, coordinating conjunctions) in lowercase, but there is a critical override: the first and last word of a title must always be capitalized regardless of their part of speech. Consider these examples: In "Of Mice and Men", "Of" is normally a small word, but because it is the first word of the title, it must be capitalized. In "A Day in the Life Of", the trailing "Of" is also normally a small word, but because it ends the title, it is capitalized. Style guides also disagree on exactly which words count as small words. AP style lowercases prepositions of four letters or fewer; Chicago Manual of Style lowercases all prepositions; APA style capitalizes prepositions of four or more letters (e.g., from, with, between). This tool uses its own fixed list of 13 small words. Two mistakes Japanese speakers (and others) often make with English titles: Mistake 1 — capitalizing every word (e.g., "THE LORD OF THE RINGS"). Mistake 2 — leaving everything lowercase (e.g., "the lord of the rings"). The correct form capitalizes each word except small words: "The Lord of the Rings".

Frequently asked questions

What is the difference between camelCase and PascalCase?

The only difference is whether the first word is lowercase or uppercase. camelCase keeps the first token lowercase (e.g., helloWorld), while PascalCase capitalizes every token including the first (e.g., HelloWorld). In practice, camelCase is used for variables and function names, while PascalCase is used for class names and React component names.

Which programming languages use snake_case?

Python recommends snake_case for variable and function names via PEP 8. Ruby and database column names also conventionally use snake_case. CONSTANT_CASE (uppercase snake) is the widely adopted convention for constants and environment variables (e.g., DATABASE_URL, MAX_RETRY) across many languages.

Why is kebab-case so common in HTML and CSS?

HTML attribute names are case-insensitive, so lowercase-with-hyphens is the safest and most portable choice. CSS custom properties (--main-color) and class names naturally use the same style. npm package names and URL slugs follow the same convention. However, kebab-case cannot be used for JavaScript variable names because the hyphen (-) is interpreted as the subtraction operator, causing a syntax error.

What happens if my text contains Japanese characters?

Only the Latin letters (A–Z, a–z) are transformed; Japanese characters are preserved exactly as entered. For example, converting "こんにちは World" to UPPERCASE gives "こんにちは WORLD". If you need to convert full-width ASCII characters (Ａ, Ｂ, Ｃ…) to half-width, use the Fullwidth Converter tool instead.

Why doesn't "the" get capitalized in Title Case?

English headline style keeps articles, short prepositions, and coordinating conjunctions lowercase. This tool's small-word list is: the, a, an, of, in, on, at, for, but, nor, or, so, yet (13 words). However, the first and last word of a title are always capitalized regardless — so "the" at the start of a title becomes "The". Style guides (Chicago, AP, APA) differ slightly on which words belong in the small-word list, so always verify against your target guide for formal publishing. Character Counter

Related Tools

• →Character Counter
• →Fancy Text Generator