ケース変換
テキストを大文字、小文字、タイトルケース、センテンスケースに変換。無料。
What is a case converter?
A case converter instantly changes the capitalization style of your text: UPPERCASE, lowercase, Title Case, or Sentence case. It saves you from retyping or manually fixing a block of text — instead of deleting and correcting a sentence letter by letter, you paste it and pick the style you need in one click.
Case conversion matters everywhere text is formatted: headings and buttons look cleaner in Title Case, emails and usernames are often stored in lowercase, and all-caps text is used for acronyms and warning labels. This free case converter runs entirely in your browser, supports UPPERCASE, lowercase, Title Case, and Sentence case, and leaves the rest of your text untouched.
使い方 use the case converter
- Paste or type your text into the box above, or write it directly.
- Pick the style you need — UPPERCASE, lowercase, Title Case, or Sentence case.
- Review the converted text and hit コピー to use it wherever you need it.
Frequently asked questions
What cases are supported?
UPPERCASE, lowercase, Title Case, and Sentence case. UPPERCASE capitalizes every letter, lowercase converts everything to small letters, Title Case capitalizes the start of each word, and Sentence case capitalizes the start of each sentence.
Is it free?
Yes, free with no limits or signup. 変換 as much text as you need, and everything runs locally in your browser.
Does it change numbers or punctuation?
No — only letters change case. Digits, punctuation, spaces, and symbols are copied to the output exactly as you typed them.
What is the difference between title case and sentence case?
Title Case capitalizes the first letter of every word, like a book title. Sentence case capitalizes only the first word of each sentence, like normal writing.