ROT13 Encoder/Decoder
Rotate letters by 13 positions. Encoding and decoding are the same operation.
About ROT13
ROT13 is a simple substitution cipher that rotates each letter by 13 places in the alphabet. Applying ROT13 twice returns the original text.
About this ROT13 Encoder/Decoder
Encode or decode text with the ROT13 cipher. ROT13 shifts each letter by 13 positions in the alphabet (A→N, B→O, etc.), so encoding and decoding are the same operation. It's not encryption—it's used for hiding spoilers, obfuscating jokes, or simple puzzles. All processing runs in your browser.
Key Features
Encode and decode ROT13 (same operation)
Handles uppercase and lowercase
Leaves numbers and symbols unchanged
Instant conversion as you type
Copy result to clipboard
Works entirely in your browser
How to Use
Enter or paste text to encode or decode
Click Encode/Decode (ROT13 is reversible with the same action)
View the result and copy if needed
Use for spoilers, puzzles, or simple obfuscation
Popular Use Cases
Hide spoilers in forum posts
Obfuscate punchlines or answers
Simple cipher puzzles and education
Legacy compatibility (e.g. Usenet)
Lightweight text scrambling
Tips & Best Practices
ROT13 only affects A–Z and a–z; numbers and punctuation stay the same
Applying ROT13 twice returns the original text
ROT13 is not secure; anyone can decode it instantly
Use for fun or spoilers, not for real secrecy
Frequently Asked Questions
What is ROT13?
ROT13 (rotate by 13) is a letter substitution cipher that replaces each letter with the letter 13 positions later in the alphabet. Because the alphabet has 26 letters, applying ROT13 twice gives you the original text.
Is ROT13 encryption?
No. ROT13 provides no security—it's trivially reversible. It's used for hiding spoilers or making text slightly harder to read at a glance, not for protecting sensitive data.
Why does encode and decode do the same thing?
Since rotating by 13 twice brings you back to the start (13+13=26), encoding and decoding are the same operation. One click encodes; another click decodes.
Does ROT13 work on numbers?
No. ROT13 only shifts letters A–Z and a–z. Numbers, spaces, and punctuation are left unchanged.
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