ROT13 Encoder & Decoder
Apply ROT13 or any rotation cipher to your text. Encoding and decoding use the same operation — just paste and convert.
Free ROT13 Cipher Tool
ROT13 (rotate by 13 places) 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 — meaning the same operation both encodes and decodes.
How ROT13 Works
Each letter is shifted by 13 positions: A becomes N, B becomes O, C becomes P, and so on. After Z, it wraps back to A. Numbers, spaces, and special characters remain unchanged. ROT13 is its own inverse — applying it to encoded text returns the original, making it one of the simplest symmetric ciphers.
Other Rotation Values
While ROT13 is the most common, any rotation from 1 to 25 is valid. ROT1 (shift by 1) is the classic Caesar cipher used by Julius Caesar. ROT25 is equivalent to shifting backward by 1. This tool supports all rotation values from 1 to 25, including custom values.
Frequently Asked Questions
No. ROT13 is not encryption — it's a simple obfuscation technique. It's trivially easy to decode and should never be used for protecting sensitive information. It's commonly used to hide spoilers, punchlines, or puzzle answers online.
ROT13 is unique because 13 is exactly half of 26 (the alphabet length). This means encoding and decoding use the same operation. For other rotation values, you need to apply the complementary rotation to decode (e.g., ROT3 encoding requires ROT23 decoding).