タイムゾーン変換
テキストを大文字、小文字、タイトルケース、キャメルケース、パスカルケース、スネークケース、ケバブケースに即座に変換します。
このツールについて
必要なケース形式にテキストを変換します。プログラミングケース形式（キャメルケース、パスカルケース、スネークケース、ケバブケース）と標準的な文章形式（大文字、小文字、タイトル、センテンス）を含む8つの変換モードをサポートしています。コーディング、SEO、コンテンツライティングに役立ちます。
使い方
- 1 入力フィールドにテキストを貼り付けるか入力してください。
- 2 任意の変換ボタンをクリックしてそのケース形式を適用してください。
- 3 変換されたテキストが出力フィールドに即座に表示されます。
- 4 「コピー」をクリックして結果をコピーしてください。
What "case" really means in text and code
Letter case is more than an aesthetic choice. In prose, capitalization signals the start of a sentence or a proper noun. In code, the case convention you pick is a hard rule enforced by linters, style guides, and sometimes the language itself: userId and user_id are two different identifiers, and mixing them breaks software. This converter does the tedious re-typing for you, transforming a single block of text into any of ten case styles instantly and entirely inside your browser.
The ten formats and where each belongs
| Format | "hello world example" becomes | Typical use |
|---|---|---|
| UPPERCASE | HELLO WORLD EXAMPLE | Headings, emphasis, constants in legacy code |
| lowercase | hello world example | Tags, email addresses, normalization |
| Title Case | Hello World Example | Headlines, book and article titles |
| Sentence case | Hello world example | Body copy, UI labels, descriptions |
| camelCase | helloWorldExample | JavaScript and Java variables, JSON keys |
| PascalCase | HelloWorldExample | Class and component names |
| snake_case | hello_world_example | Python variables, database columns |
| kebab-case | hello-world-example | URL slugs, CSS classes, HTML attributes |
| CONSTANT_CASE | HELLO_WORLD_EXAMPLE | Environment variables, fixed constants |
| dot.case | hello.world.example | Config keys, namespaced properties |
How the converter splits words — and why that matters
Every transformation starts by breaking your text into words. The clever part is that the tool recognizes boundaries that have no visible separator. It inserts a split between a lowercase letter and an uppercase one (so helloWorld is read as two words), and it handles runs of capitals followed by a capitalized word (so HTMLParser splits into HTML and Parser rather than HTM and LParser). It also treats hyphens, underscores, dots, and spaces as separators. This means you can paste text already in any case and convert it cleanly to another — you are not limited to space-separated input.
A worked example
Paste getHTTPResponseCode and click snake_case. The splitter first sees the lowercase-to-uppercase jump after get, then the capital run HTTP followed by Response, giving the words get, HTTP, Response, Code. Each is lowercased and joined with underscores, producing get_http_response_code. Click kebab-case on the same input and you get get-http-response-code — ideal as a URL slug or CSS class.
Practical use cases
- Renaming variables across languages. Porting a Python
snake_casefield into a JavaScript object? Convert tocamelCasein one click instead of editing each character. - Generating URL slugs. Turn an article title like "10 Tips for Faster Builds" into
10-tips-for-faster-buildswith kebab-case. - Cleaning up headlines. Title Case fixes inconsistent capitalization when you have copied a heading from a messy source.
- Building constants. CONSTANT_CASE produces ready-to-paste environment variable names such as
DATABASE_CONNECTION_URL.
Things Title Case and Sentence case do not do
Be aware of the limits of any automatic case tool, this one included. Title Case here capitalizes the first letter of every word; it does not apply the editorial rule that small words like "of", "the", and "and" stay lowercase. If you need strict AP or Chicago style, review the output by hand. Sentence case capitalizes the first letter and the first letter after each period, exclamation mark, or question mark — so it will not know that "iPhone" or "NASA" should keep their original capitals. Re-capitalize proper nouns and acronyms after converting.
Common mistakes to avoid
- Losing acronym casing. Converting
parseJSONto Title Case yields "Parse Json", not "Parse JSON". Acronyms get folded to ordinary words because the tool cannot know which letters are an abbreviation. - Expecting punctuation to survive. The programming formats (camel, snake, kebab, etc.) strip separators by design. If your text contains meaningful commas or slashes, they will be absorbed as word boundaries.
- Converting code that relies on exact identifiers. Never bulk-convert a whole source file's case; you will rename keywords and string literals too. Convert individual identifiers only.
Privacy
The conversion runs as plain JavaScript on your device. Your text is never uploaded, logged, or sent to a server — you can disconnect from the internet and every button still works. Use the Swap control to move the output back into the input box and chain conversions, for example lowercase first, then snake_case.