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ROT13 Encoder

Encode or decode text using the ROT13 cipher instantly. ROT13 is its own inverse — the same tool both encodes and decodes your message.

Used 52.7K times today

ROT13 shifts each letter by 13 positions. Applying it twice returns the original text.

How to Use ROT13 Encoder

  1. 1

    Enter your text

    Type or paste the message you want to encode or decode using ROT13.

  2. 2

    Apply ROT13

    Click the Encode/Decode button. Since ROT13 is symmetric, the same action both encodes and decodes.

  3. 3

    Copy the result

    Copy the transformed text to share or use wherever you need it.

Frequently Asked Questions

What is ROT13?
ROT13 is a simple letter substitution cipher that replaces each letter with the letter 13 positions ahead of it in the alphabet. It is a special case of the Caesar cipher.
Why is ROT13 its own inverse?
Because the Latin alphabet has 26 letters, shifting by 13 and then shifting by 13 again returns to the original letter. So encoding and decoding use the exact same operation.
Does ROT13 work on numbers and punctuation?
No. ROT13 only rotates alphabetic characters (A–Z and a–z). Numbers, spaces, and punctuation are passed through unchanged.

About ROT13 Encoder

The ROT13 Encoder on Utilko implements the classic ROT13 substitution cipher — a lightweight obfuscation technique widely used in online forums to hide spoilers, punchlines, and puzzle solutions from casual readers. Because ROT13 is its own mathematical inverse, the same tool both encrypts and decrypts your message with one click.

ROT13 is not a secure encryption method and should not be used to protect sensitive information. However, it remains a popular tool for developers learning about ciphers, puzzle makers hiding answers, and community moderators who want to conceal spoilers without complex tooling.

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