ケース変換
文頭大文字、タイトルケース、大文字・小文字、開発者向け命名スタイルを変換。各ツールは1ルール — 貼り付けテキストの整形に連鎖できます。
Start with the right style
どの形式か迷ったら、テキストケースの完全ガイドを読み、見出し・本文・スラッグ・コード識別子に合う変換を選びます。
Writing and publishing case styles
文頭大文字とタイトルケースは公開向け。大文字・小文字はCaps Lockやスラッグ向け。camelCase、PascalCase、snake_case、kebab-caseはコードとURL向け。
Developer naming conventions
camelCase fits JavaScript variables, PascalCase fits React components and classes, snake_case fits Python and SQL columns, and kebab-case fits URL paths and CSS classes. CONSTANT_CASE and dot.case cover env vars and namespaced config keys.
Which case should I use?
Use sentence case for paragraphs, emails, and most UI copy. Use title case for headlines, blog post titles, and slide titles. Use uppercase sparingly for labels or fixing caps-lock mistakes. Use lowercase before URL slugs or when normalizing messy input. For code, match your language: camelCase for JavaScript variables, PascalCase for classes and components, snake_case for Python and SQL, kebab-case for URLs and CSS classes, and CONSTANT_CASE for environment variables.
Pick one tool per job
Each converter on this page targets one capitalization rule. Chain tools when you need to normalize shouting input to lowercase, then title-case only the headline. Read the comparison guides on the blog when you are unsure which style your style guide expects.
Which text case should you use?
| Case | Example | Common use |
|---|---|---|
| Sentence case | Hello world | Body copy, emails, UI strings |
| Title Case | Hello World | Headlines, blog titles, slide titles |
| UPPERCASE | HELLO WORLD | Labels, emphasis, fixing caps-lock |
| lowercase | hello world | URLs, text normalization |
| Capitalized Case | Hello World | Every word capitalized (not style-guide title case) |
| camelCase | helloWorld | JavaScript variables, JSON keys |
| PascalCase | HelloWorld | Classes, React components, types |
| snake_case | hello_world | Python, SQL columns, data files |
| kebab-case | hello-world | URL slugs, CSS classes, CLI flags |
| CONSTANT_CASE | HELLO_WORLD | Environment variables, enums |
| dot.case | hello.world | i18n keys, config paths |
Tools in this category
Uppercase Converter
Turn any text into UPPERCASE instantly.
Lowercase Converter
Fix caps-lock mistakes or normalize headings: instant lowercase conversion.
文頭大文字変換
Normalize messy copy: each sentence starts with a capital; the rest goes lowercase.
Title Case変換
Format titles the right way: major words capitalized, minor words handled correctly.
Capitalized Case Converter
Convert any text to Capitalized Case instantly.
Alternating Case Converter
Turn any sentence into alternating uppercase and lowercase letters.
Inverse Case Converter
Invert uppercase and lowercase letters to fix Caps Lock mistakes.
camelCase変換
Convert text to camelCase for JavaScript variables, API fields, and code examples.
PascalCase Converter
Convert text to PascalCase for React components, classes, TypeScript types, and code identifiers.
snake_case Converter
Convert text to snake_case for Python variables, database columns, filenames, and config keys.
kebab-case Converter
Convert text to kebab-case for URL slugs, CSS classes, package names, and CLI flags.
CONSTANT_CASE Converter
Convert text to CONSTANT_CASE for environment variables, enum values, feature flags, and shared constants.
dot.case Converter
Convert text to dot.case for translation keys, config paths, analytics events, and namespaced labels.
Frequently asked questions
ブログタイトルはどのスタイル？
多くの媒体はタイトルにタイトルケース、小見出しに文頭大文字。社内ガイドを確認してください。
貼り付けたテキストはアップロードされますか？
標準コンバーターはページ読み込み後、このブラウザで動作します。アカウント不要です。
コードの変数名にも使えますか？
はい。camelCase、PascalCase、snake_case、kebab-case。変換後にブランド名や略語を確認してください。