ROT13 Encoder / Decoder
Encode and decode text with ROT13 and other rotation ciphers.
How to Use the ROT13 Encoder / Decoder
Paste or type your text into the input box. The output updates live as you type.
- ROT13 (default) — the classic rotation cipher. Apply it once to encode, apply it again to decode.
- Custom rotation — drag the slider to choose any rotation from ROT1 to ROT25 for a general Caesar cipher.
- Copy — click the Copy button to copy the result to your clipboard.
Numbers, punctuation and whitespace are passed through unchanged — only A-Z and a-z letters are rotated.
Frequently Asked Questions
What is ROT13?
ROT13 is a letter substitution cipher that replaces each letter with the letter 13 positions after it in the alphabet. Because the English alphabet has 26 letters, applying ROT13 twice returns the original text.
How is ROT13 related to Caesar cipher?
ROT13 is a special case of the Caesar cipher with a fixed shift of 13. The slider lets you use any shift from 1 to 25, covering all Caesar cipher variants.
Does this tool handle numbers and special characters?
Numbers, punctuation, spaces and other non-letter characters are left unchanged. Only English letters (A-Z, a-z) are rotated.
Is ROT13 encryption secure?
No. ROT13 and Caesar ciphers are trivially easy to break and should never be used for real security. They are mainly used for obscuring spoilers, puzzle answers, or light obfuscation.
Is my text stored or sent to a server?
No. All encoding and decoding happens locally in your browser. Your text never leaves your device.
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