小文字を大文字に
小文字のテキストをオンラインで大文字に変換 — 即時、無料、プライベート。テキストがブラウザ外に出ることはありません。
Why convert lowercase to uppercase?
Changing lowercase text to UPPERCASE is useful for headings, acronyms, labels, ticker text, and legacy systems that store data in capitals. Writers use it to emphasize a word, developers normalize keys and constants with it, and designers rely on it for all-caps typography.
This converter turns any lowercase text into UPPERCASE the moment you type it. Only letters change case — digits, punctuation, spaces, and symbols stay exactly as they are, so code and formatted text remain intact. Everything runs in your browser: no upload, no signup, no limits.
使い方 use the uppercase converter
- Type or paste your text into the box above — conversion is live.
- Check the UPPERCASE result and its character count.
- Hit コピー to put the converted text on your clipboard.
Frequently asked questions
How do I change lowercase to uppercase?
Paste your text and click 変換 to UPPERCASE — or simply start typing, because the tool converts live on input. The result appears instantly with a copy button.
Does it handle digits, symbols, and accented letters?
Yes. Letters are uppercased (é becomes É); digits, punctuation, and symbols are left untouched, so the tool is safe for mixed content like code or headers.
Can it also convert to lowercase?
Yes — use the dedicated 小文字変換 for the reverse direction, or the ケース変換 if you also need Title Case and Sentence case.
Is this tool private?
Completely. All conversion happens locally in your browser with vanilla JavaScript — nothing is uploaded, stored, or tracked.