ROT13 Encoder / Decoder
Apply ROT13 cipher to text — shift each letter by 13 positions. Applying ROT13 twice returns the original text.
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The ROT13 tool applies the ROT13 substitution cipher to your text. Each letter is replaced by the letter 13 positions after it in the alphabet. Since the English alphabet has 26 letters, applying ROT13 twice returns the original text — the same function both encodes and decodes.
ROT13 was popularized on Usenet forums as a way to hide spoilers, puzzle answers, and mildly sensitive content. While it provides no real security, it prevents casual reading of text. It's also a simple example used to teach cipher concepts in cryptography courses.
This tool processes text entirely in your browser. Non-alphabetic characters (numbers, punctuation, spaces) are preserved unchanged.
How to Use ROT13 Encoder / Decoder
- 1Paste or type your text into the input area.
- 2The ROT13 transformation is applied instantly.
- 3To decode ROT13 text, simply paste the encoded text — the same operation reverses it.
- 4Copy the result using the Copy button.