Free OnlineText Tools
ROT13 Encoder/Decoder
Encode and decode text using the ROT13 cipher. Shift letters by 13 positions for simple text obfuscation online.
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Encoding Mode
ROT ciphers are symmetric -- applying the same transformation again decodes the message. Use the "Swap" button to verify.
Key Features — ROT13 Encoder/Decoder
Instant ROT13 encoding and decoding
Customizable shift value (ROT1 through ROT25)
Preserves numbers, spaces, and punctuation
Works with both uppercase and lowercase letters
Encoding and decoding use the same operation
Why Use This Tool — ROT13 Encoder/Decoder
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Works Everywhere
Use on any device — desktop, tablet, or phone. No downloads or plugins needed.
Frequently Asked Questions — ROT13 Encoder/Decoder
What is ROT13?
ROT13 is a simple letter substitution cipher that replaces each letter with the letter 13 positions after it in the alphabet. Since the English alphabet has 26 letters, applying ROT13 twice returns the original text. It is commonly used to hide spoilers and puzzle answers online.
Is ROT13 secure encryption?
No. ROT13 provides no real security. It is a simple obfuscation technique that anyone can reverse. It is useful for hiding text from casual reading, such as spoilers or punchlines, but should never be used to protect sensitive information.
Why is ROT13 its own inverse?
Because the English alphabet has 26 letters and 13 is exactly half of 26, shifting a letter forward by 13 positions and then shifting it forward by 13 more brings it back to the original letter. This means encoding and decoding are the same operation.