ROT13 Encoder & Decoder
Encode or decode ROT13 instantly. Same operation works both ways. Free, no signup.
Free ROT13 Encoder & Decoder — No Signup Required
ROT13 is a simple letter substitution cipher that replaces each letter with the letter 13 positions after it in the alphabet. Since the alphabet has 26 letters, applying ROT13 twice returns the original text — so the same operation both encodes and decodes.
How does it work?
Type or paste text in the input area. The ROT13 conversion appears instantly in real time. Numbers, spaces, and special characters remain unchanged — only letters A-Z are shifted.
Is it really free?
Yes. This tool runs entirely in your browser with zero server calls. No signup, no limits, no data collection.
What is ROT13 used for?
ROT13 is commonly used to hide spoilers, puzzle answers, and jokes in online forums. It is not secure encryption — just a simple way to obscure text so it cannot be read at a glance.
Is ROT13 secure?
No. ROT13 is a toy cipher with no security value. Anyone who knows the algorithm can decode it instantly. For actual security, use proper encryption like AES or RSA.