ROT13 エンコーダー & デコーダー
「ROT13 エンコーダー & デコーダー」はテキストと文書に使えるブラウザツールです。入力内容と結果は通常この端末内で処理され、登録は必要ありません。
使い方
使い方
- Enter up to 100,000 characters of plain text or ROT13 text.
- Apply ROT13 once to rotate every ASCII letter by 13 positions.
- Review the exact result, then copy it or download a text file. Apply ROT13 again to restore the original.
One symmetric letter substitution
ROT13 maps A–M to N–Z and N–Z back to A–M, with the same rule for lowercase letters. Because the alphabet contains 26 letters, applying the transformation twice restores the exact browser text value.
A deliberately narrow character scope
Only the ASCII ranges A–Z and a–z change. Digits, punctuation, whitespace, line breaks, accented letters, other scripts, emoji, and every remaining UTF-16 code unit in the browser text value stay in their original positions. Output length therefore always equals input length.
よくある質問
あわせて知りたいこと
Do I choose between encode and decode?
No. ROT13 uses the same operation in both directions. Apply it once to transform the text and a second time to restore the source.
Will accented or non-English letters change?
No. ROT13 is defined here only for the 26 ASCII English letters. Characters such as é, ñ, 中文, and emoji remain unchanged.
Is ROT13 secure encryption?
No. It is a simple, widely recognizable substitution used for obfuscation and puzzles. Anyone can reverse it immediately by applying ROT13 again.