ROT13 Encoder & Decoder Online Free — Text Cipher
Apply ROT13 cipher to encode or decode text instantly.
What is ROT13 Encoder / Decoder?
Applies the ROT13 substitution cipher, rotating each letter by 13 positions in the alphabet. Since the alphabet has 26 letters, ROT13 is its own inverse — applying it twice returns the original text.
Common Use Cases
Hiding spoilers in online posts, obfuscating answers in quizzes, classic puzzle encoding, and understanding simple substitution ciphers.
How It Works
Each letter a–z and A–Z is shifted by 13 positions. Non-letter characters (digits, spaces, punctuation) are unchanged. Applying ROT13 twice returns the original text.
Frequently Asked Questions
Is ROT13 a secure cipher?
No. ROT13 provides no real security — it is trivially reversible. It is used for casual obfuscation only.
Does ROT13 affect numbers or punctuation?
No. Only letters are rotated. Numbers, spaces, and punctuation pass through unchanged.
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